Colors in JavaScript console

In Chrome & Firefox (+31) you can add CSS in console.log messages:

console.log('%c Oh my heavens! ', 'background: #222; color: #bada55');

https://i.stack.imgur.com/gvpgF.png

https://i.stack.imgur.com/DFJBd.png

References

MDN: Styling console output

Chrome: Console API Reference

---

Here is an extreme example with rainbow drop shadow.

var css = "text-shadow: -1px -1px hsl(0,100%,50%), 1px 1px hsl(5.4, 100%, 50%), 3px 2px hsl(10.8, 100%, 50%), 5px 3px hsl(16.2, 100%, 50%), 7px 4px hsl(21.6, 100%, 50%), 9px 5px hsl(27, 100%, 50%), 11px 6px hsl(32.4, 100%, 50%), 13px 7px hsl(37.8, 100%, 50%), 14px 8px hsl(43.2, 100%, 50%), 16px 9px hsl(48.6, 100%, 50%), 18px 10px hsl(54, 100%, 50%), 20px 11px hsl(59.4, 100%, 50%), 22px 12px hsl(64.8, 100%, 50%), 23px 13px hsl(70.2, 100%, 50%), 25px 14px hsl(75.6, 100%, 50%), 27px 15px hsl(81, 100%, 50%), 28px 16px hsl(86.4, 100%, 50%), 30px 17px hsl(91.8, 100%, 50%), 32px 18px hsl(97.2, 100%, 50%), 33px 19px hsl(102.6, 100%, 50%), 35px 20px hsl(108, 100%, 50%), 36px 21px hsl(113.4, 100%, 50%), 38px 22px hsl(118.8, 100%, 50%), 39px 23px hsl(124.2, 100%, 50%), 41px 24px hsl(129.6, 100%, 50%), 42px 25px hsl(135, 100%, 50%), 43px 26px hsl(140.4, 100%, 50%), 45px 27px hsl(145.8, 100%, 50%), 46px 28px hsl(151.2, 100%, 50%), 47px 29px hsl(156.6, 100%, 50%), 48px 30px hsl(162, 100%, 50%), 49px 31px hsl(167.4, 100%, 50%), 50px 32px hsl(172.8, 100%, 50%), 51px 33px hsl(178.2, 100%, 50%), 52px 34px hsl(183.6, 100%, 50%), 53px 35px hsl(189, 100%, 50%), 54px 36px hsl(194.4, 100%, 50%), 55px 37px hsl(199.8, 100%, 50%), 55px 38px hsl(205.2, 100%, 50%), 56px 39px hsl(210.6, 100%, 50%), 57px 40px hsl(216, 100%, 50%), 57px 41px hsl(221.4, 100%, 50%), 58px 42px hsl(226.8, 100%, 50%), 58px 43px hsl(232.2, 100%, 50%), 58px 44px hsl(237.6, 100%, 50%), 59px 45px hsl(243, 100%, 50%), 59px 46px hsl(248.4, 100%, 50%), 59px 47px hsl(253.8, 100%, 50%), 59px 48px hsl(259.2, 100%, 50%), 59px 49px hsl(264.6, 100%, 50%), 60px 50px hsl(270, 100%, 50%), 59px 51px hsl(275.4, 100%, 50%), 59px 52px hsl(280.8, 100%, 50%), 59px 53px hsl(286.2, 100%, 50%), 59px 54px hsl(291.6, 100%, 50%), 59px 55px hsl(297, 100%, 50%), 58px 56px hsl(302.4, 100%, 50%), 58px 57px hsl(307.8, 100%, 50%), 58px 58px hsl(313.2, 100%, 50%), 57px 59px hsl(318.6, 100%, 50%), 57px 60px hsl(324, 100%, 50%), 56px 61px hsl(329.4, 100%, 50%), 55px 62px hsl(334.8, 100%, 50%), 55px 63px hsl(340.2, 100%, 50%), 54px 64px hsl(345.6, 100%, 50%), 53px 65px hsl(351, 100%, 50%), 52px 66px hsl(356.4, 100%, 50%), 51px 67px hsl(361.8, 100%, 50%), 50px 68px hsl(367.2, 100%, 50%), 49px 69px hsl(372.6, 100%, 50%), 48px 70px hsl(378, 100%, 50%), 47px 71px hsl(383.4, 100%, 50%), 46px 72px hsl(388.8, 100%, 50%), 45px 73px hsl(394.2, 100%, 50%), 43px 74px hsl(399.6, 100%, 50%), 42px 75px hsl(405, 100%, 50%), 41px 76px hsl(410.4, 100%, 50%), 39px 77px hsl(415.8, 100%, 50%), 38px 78px hsl(421.2, 100%, 50%), 36px 79px hsl(426.6, 100%, 50%), 35px 80px hsl(432, 100%, 50%), 33px 81px hsl(437.4, 100%, 50%), 32px 82px hsl(442.8, 100%, 50%), 30px 83px hsl(448.2, 100%, 50%), 28px 84px hsl(453.6, 100%, 50%), 27px 85px hsl(459, 100%, 50%), 25px 86px hsl(464.4, 100%, 50%), 23px 87px hsl(469.8, 100%, 50%), 22px 88px hsl(475.2, 100%, 50%), 20px 89px hsl(480.6, 100%, 50%), 18px 90px hsl(486, 100%, 50%), 16px 91px hsl(491.4, 100%, 50%), 14px 92px hsl(496.8, 100%, 50%), 13px 93px hsl(502.2, 100%, 50%), 11px 94px hsl(507.6, 100%, 50%), 9px 95px hsl(513, 100%, 50%), 7px 96px hsl(518.4, 100%, 50%), 5px 97px hsl(523.8, 100%, 50%), 3px 98px hsl(529.2, 100%, 50%), 1px 99px hsl(534.6, 100%, 50%), 7px 100px hsl(540, 100%, 50%), -1px 101px hsl(545.4, 100%, 50%), -3px 102px hsl(550.8, 100%, 50%), -5px 103px hsl(556.2, 100%, 50%), -7px 104px hsl(561.6, 100%, 50%), -9px 105px hsl(567, 100%, 50%), -11px 106px hsl(572.4, 100%, 50%), -13px 107px hsl(577.8, 100%, 50%), -14px 108px hsl(583.2, 100%, 50%), -16px 109px hsl(588.6, 100%, 50%), -18px 110px hsl(594, 100%, 50%), -20px 111px hsl(599.4, 100%, 50%), -22px 112px hsl(604.8, 100%, 50%), -23px 113px hsl(610.2, 100%, 50%), -25px 114px hsl(615.6, 100%, 50%), -27px 115px hsl(621, 100%, 50%), -28px 116px hsl(626.4, 100%, 50%), -30px 117px hsl(631.8, 100%, 50%), -32px 118px hsl(637.2, 100%, 50%), -33px 119px hsl(642.6, 100%, 50%), -35px 120px hsl(648, 100%, 50%), -36px 121px hsl(653.4, 100%, 50%), -38px 122px hsl(658.8, 100%, 50%), -39px 123px hsl(664.2, 100%, 50%), -41px 124px hsl(669.6, 100%, 50%), -42px 125px hsl(675, 100%, 50%), -43px 126px hsl(680.4, 100%, 50%), -45px 127px hsl(685.8, 100%, 50%), -46px 128px hsl(691.2, 100%, 50%), -47px 129px hsl(696.6, 100%, 50%), -48px 130px hsl(702, 100%, 50%), -49px 131px hsl(707.4, 100%, 50%), -50px 132px hsl(712.8, 100%, 50%), -51px 133px hsl(718.2, 100%, 50%), -52px 134px hsl(723.6, 100%, 50%), -53px 135px hsl(729, 100%, 50%), -54px 136px hsl(734.4, 100%, 50%), -55px 137px hsl(739.8, 100%, 50%), -55px 138px hsl(745.2, 100%, 50%), -56px 139px hsl(750.6, 100%, 50%), -57px 140px hsl(756, 100%, 50%), -57px 141px hsl(761.4, 100%, 50%), -58px 142px hsl(766.8, 100%, 50%), -58px 143px hsl(772.2, 100%, 50%), -58px 144px hsl(777.6, 100%, 50%), -59px 145px hsl(783, 100%, 50%), -59px 146px hsl(788.4, 100%, 50%), -59px 147px hsl(793.8, 100%, 50%), -59px 148px hsl(799.2, 100%, 50%), -59px 149px hsl(804.6, 100%, 50%), -60px 150px hsl(810, 100%, 50%), -59px 151px hsl(815.4, 100%, 50%), -59px 152px hsl(820.8, 100%, 50%), -59px 153px hsl(826.2, 100%, 50%), -59px 154px hsl(831.6, 100%, 50%), -59px 155px hsl(837, 100%, 50%), -58px 156px hsl(842.4, 100%, 50%), -58px 157px hsl(847.8, 100%, 50%), -58px 158px hsl(853.2, 100%, 50%), -57px 159px hsl(858.6, 100%, 50%), -57px 160px hsl(864, 100%, 50%), -56px 161px hsl(869.4, 100%, 50%), -55px 162px hsl(874.8, 100%, 50%), -55px 163px hsl(880.2, 100%, 50%), -54px 164px hsl(885.6, 100%, 50%), -53px 165px hsl(891, 100%, 50%), -52px 166px hsl(896.4, 100%, 50%), -51px 167px hsl(901.8, 100%, 50%), -50px 168px hsl(907.2, 100%, 50%), -49px 169px hsl(912.6, 100%, 50%), -48px 170px hsl(918, 100%, 50%), -47px 171px hsl(923.4, 100%, 50%), -46px 172px hsl(928.8, 100%, 50%), -45px 173px hsl(934.2, 100%, 50%), -43px 174px hsl(939.6, 100%, 50%), -42px 175px hsl(945, 100%, 50%), -41px 176px hsl(950.4, 100%, 50%), -39px 177px hsl(955.8, 100%, 50%), -38px 178px hsl(961.2, 100%, 50%), -36px 179px hsl(966.6, 100%, 50%), -35px 180px hsl(972, 100%, 50%), -33px 181px hsl(977.4, 100%, 50%), -32px 182px hsl(982.8, 100%, 50%), -30px 183px hsl(988.2, 100%, 50%), -28px 184px hsl(993.6, 100%, 50%), -27px 185px hsl(999, 100%, 50%), -25px 186px hsl(1004.4, 100%, 50%), -23px 187px hsl(1009.8, 100%, 50%), -22px 188px hsl(1015.2, 100%, 50%), -20px 189px hsl(1020.6, 100%, 50%), -18px 190px hsl(1026, 100%, 50%), -16px 191px hsl(1031.4, 100%, 50%), -14px 192px hsl(1036.8, 100%, 50%), -13px 193px hsl(1042.2, 100%, 50%), -11px 194px hsl(1047.6, 100%, 50%), -9px 195px hsl(1053, 100%, 50%), -7px 196px hsl(1058.4, 100%, 50%), -5px 197px hsl(1063.8, 100%, 50%), -3px 198px hsl(1069.2, 100%, 50%), -1px 199px hsl(1074.6, 100%, 50%), -1px 200px hsl(1080, 100%, 50%), 1px 201px hsl(1085.4, 100%, 50%), 3px 202px hsl(1090.8, 100%, 50%), 5px 203px hsl(1096.2, 100%, 50%), 7px 204px hsl(1101.6, 100%, 50%), 9px 205px hsl(1107, 100%, 50%), 11px 206px hsl(1112.4, 100%, 50%), 13px 207px hsl(1117.8, 100%, 50%), 14px 208px hsl(1123.2, 100%, 50%), 16px 209px hsl(1128.6, 100%, 50%), 18px 210px hsl(1134, 100%, 50%), 20px 211px hsl(1139.4, 100%, 50%), 22px 212px hsl(1144.8, 100%, 50%), 23px 213px hsl(1150.2, 100%, 50%), 25px 214px hsl(1155.6, 100%, 50%), 27px 215px hsl(1161, 100%, 50%), 28px 216px hsl(1166.4, 100%, 50%), 30px 217px hsl(1171.8, 100%, 50%), 32px 218px hsl(1177.2, 100%, 50%), 33px 219px hsl(1182.6, 100%, 50%), 35px 220px hsl(1188, 100%, 50%), 36px 221px hsl(1193.4, 100%, 50%), 38px 222px hsl(1198.8, 100%, 50%), 39px 223px hsl(1204.2, 100%, 50%), 41px 224px hsl(1209.6, 100%, 50%), 42px 225px hsl(1215, 100%, 50%), 43px 226px hsl(1220.4, 100%, 50%), 45px 227px hsl(1225.8, 100%, 50%), 46px 228px hsl(1231.2, 100%, 50%), 47px 229px hsl(1236.6, 100%, 50%), 48px 230px hsl(1242, 100%, 50%), 49px 231px hsl(1247.4, 100%, 50%), 50px 232px hsl(1252.8, 100%, 50%), 51px 233px hsl(1258.2, 100%, 50%), 52px 234px hsl(1263.6, 100%, 50%), 53px 235px hsl(1269, 100%, 50%), 54px 236px hsl(1274.4, 100%, 50%), 55px 237px hsl(1279.8, 100%, 50%), 55px 238px hsl(1285.2, 100%, 50%), 56px 239px hsl(1290.6, 100%, 50%), 57px 240px hsl(1296, 100%, 50%), 57px 241px hsl(1301.4, 100%, 50%), 58px 242px hsl(1306.8, 100%, 50%), 58px 243px hsl(1312.2, 100%, 50%), 58px 244px hsl(1317.6, 100%, 50%), 59px 245px hsl(1323, 100%, 50%), 59px 246px hsl(1328.4, 100%, 50%), 59px 247px hsl(1333.8, 100%, 50%), 59px 248px hsl(1339.2, 100%, 50%), 59px 249px hsl(1344.6, 100%, 50%), 60px 250px hsl(1350, 100%, 50%), 59px 251px hsl(1355.4, 100%, 50%), 59px 252px hsl(1360.8, 100%, 50%), 59px 253px hsl(1366.2, 100%, 50%), 59px 254px hsl(1371.6, 100%, 50%), 59px 255px hsl(1377, 100%, 50%), 58px 256px hsl(1382.4, 100%, 50%), 58px 257px hsl(1387.8, 100%, 50%), 58px 258px hsl(1393.2, 100%, 50%), 57px 259px hsl(1398.6, 100%, 50%), 57px 260px hsl(1404, 100%, 50%), 56px 261px hsl(1409.4, 100%, 50%), 55px 262px hsl(1414.8, 100%, 50%), 55px 263px hsl(1420.2, 100%, 50%), 54px 264px hsl(1425.6, 100%, 50%), 53px 265px hsl(1431, 100%, 50%), 52px 266px hsl(1436.4, 100%, 50%), 51px 267px hsl(1441.8, 100%, 50%), 50px 268px hsl(1447.2, 100%, 50%), 49px 269px hsl(1452.6, 100%, 50%), 48px 270px hsl(1458, 100%, 50%), 47px 271px hsl(1463.4, 100%, 50%), 46px 272px hsl(1468.8, 100%, 50%), 45px 273px hsl(1474.2, 100%, 50%), 43px 274px hsl(1479.6, 100%, 50%), 42px 275px hsl(1485, 100%, 50%), 41px 276px hsl(1490.4, 100%, 50%), 39px 277px hsl(1495.8, 100%, 50%), 38px 278px hsl(1501.2, 100%, 50%), 36px 279px hsl(1506.6, 100%, 50%), 35px 280px hsl(1512, 100%, 50%), 33px 281px hsl(1517.4, 100%, 50%), 32px 282px hsl(1522.8, 100%, 50%), 30px 283px hsl(1528.2, 100%, 50%), 28px 284px hsl(1533.6, 100%, 50%), 27px 285px hsl(1539, 100%, 50%), 25px 286px hsl(1544.4, 100%, 50%), 23px 287px hsl(1549.8, 100%, 50%), 22px 288px hsl(1555.2, 100%, 50%), 20px 289px hsl(1560.6, 100%, 50%), 18px 290px hsl(1566, 100%, 50%), 16px 291px hsl(1571.4, 100%, 50%), 14px 292px hsl(1576.8, 100%, 50%), 13px 293px hsl(1582.2, 100%, 50%), 11px 294px hsl(1587.6, 100%, 50%), 9px 295px hsl(1593, 100%, 50%), 7px 296px hsl(1598.4, 100%, 50%), 5px 297px hsl(1603.8, 100%, 50%), 3px 298px hsl(1609.2, 100%, 50%), 1px 299px hsl(1614.6, 100%, 50%), 2px 300px hsl(1620, 100%, 50%), -1px 301px hsl(1625.4, 100%, 50%), -3px 302px hsl(1630.8, 100%, 50%), -5px 303px hsl(1636.2, 100%, 50%), -7px 304px hsl(1641.6, 100%, 50%), -9px 305px hsl(1647, 100%, 50%), -11px 306px hsl(1652.4, 100%, 50%), -13px 307px hsl(1657.8, 100%, 50%), -14px 308px hsl(1663.2, 100%, 50%), -16px 309px hsl(1668.6, 100%, 50%), -18px 310px hsl(1674, 100%, 50%), -20px 311px hsl(1679.4, 100%, 50%), -22px 312px hsl(1684.8, 100%, 50%), -23px 313px hsl(1690.2, 100%, 50%), -25px 314px hsl(1695.6, 100%, 50%), -27px 315px hsl(1701, 100%, 50%), -28px 316px hsl(1706.4, 100%, 50%), -30px 317px hsl(1711.8, 100%, 50%), -32px 318px hsl(1717.2, 100%, 50%), -33px 319px hsl(1722.6, 100%, 50%), -35px 320px hsl(1728, 100%, 50%), -36px 321px hsl(1733.4, 100%, 50%), -38px 322px hsl(1738.8, 100%, 50%), -39px 323px hsl(1744.2, 100%, 50%), -41px 324px hsl(1749.6, 100%, 50%), -42px 325px hsl(1755, 100%, 50%), -43px 326px hsl(1760.4, 100%, 50%), -45px 327px hsl(1765.8, 100%, 50%), -46px 328px hsl(1771.2, 100%, 50%), -47px 329px hsl(1776.6, 100%, 50%), -48px 330px hsl(1782, 100%, 50%), -49px 331px hsl(1787.4, 100%, 50%), -50px 332px hsl(1792.8, 100%, 50%), -51px 333px hsl(1798.2, 100%, 50%), -52px 334px hsl(1803.6, 100%, 50%), -53px 335px hsl(1809, 100%, 50%), -54px 336px hsl(1814.4, 100%, 50%), -55px 337px hsl(1819.8, 100%, 50%), -55px 338px hsl(1825.2, 100%, 50%), -56px 339px hsl(1830.6, 100%, 50%), -57px 340px hsl(1836, 100%, 50%), -57px 341px hsl(1841.4, 100%, 50%), -58px 342px hsl(1846.8, 100%, 50%), -58px 343px hsl(1852.2, 100%, 50%), -58px 344px hsl(1857.6, 100%, 50%), -59px 345px hsl(1863, 100%, 50%), -59px 346px hsl(1868.4, 100%, 50%), -59px 347px hsl(1873.8, 100%, 50%), -59px 348px hsl(1879.2, 100%, 50%), -59px 349px hsl(1884.6, 100%, 50%), -60px 350px hsl(1890, 100%, 50%), -59px 351px hsl(1895.4, 100%, 50%), -59px 352px hsl(1900.8, 100%, 50%), -59px 353px hsl(1906.2, 100%, 50%), -59px 354px hsl(1911.6, 100%, 50%), -59px 355px hsl(1917, 100%, 50%), -58px 356px hsl(1922.4, 100%, 50%), -58px 357px hsl(1927.8, 100%, 50%), -58px 358px hsl(1933.2, 100%, 50%), -57px 359px hsl(1938.6, 100%, 50%), -57px 360px hsl(1944, 100%, 50%), -56px 361px hsl(1949.4, 100%, 50%), -55px 362px hsl(1954.8, 100%, 50%), -55px 363px hsl(1960.2, 100%, 50%), -54px 364px hsl(1965.6, 100%, 50%), -53px 365px hsl(1971, 100%, 50%), -52px 366px hsl(1976.4, 100%, 50%), -51px 367px hsl(1981.8, 100%, 50%), -50px 368px hsl(1987.2, 100%, 50%), -49px 369px hsl(1992.6, 100%, 50%), -48px 370px hsl(1998, 100%, 50%), -47px 371px hsl(2003.4, 100%, 50%), -46px 372px hsl(2008.8, 100%, 50%), -45px 373px hsl(2014.2, 100%, 50%), -43px 374px hsl(2019.6, 100%, 50%), -42px 375px hsl(2025, 100%, 50%), -41px 376px hsl(2030.4, 100%, 50%), -39px 377px hsl(2035.8, 100%, 50%), -38px 378px hsl(2041.2, 100%, 50%), -36px 379px hsl(2046.6, 100%, 50%), -35px 380px hsl(2052, 100%, 50%), -33px 381px hsl(2057.4, 100%, 50%), -32px 382px hsl(2062.8, 100%, 50%), -30px 383px hsl(2068.2, 100%, 50%), -28px 384px hsl(2073.6, 100%, 50%), -27px 385px hsl(2079, 100%, 50%), -25px 386px hsl(2084.4, 100%, 50%), -23px 387px hsl(2089.8, 100%, 50%), -22px 388px hsl(2095.2, 100%, 50%), -20px 389px hsl(2100.6, 100%, 50%), -18px 390px hsl(2106, 100%, 50%), -16px 391px hsl(2111.4, 100%, 50%), -14px 392px hsl(2116.8, 100%, 50%), -13px 393px hsl(2122.2, 100%, 50%), -11px 394px hsl(2127.6, 100%, 50%), -9px 395px hsl(2133, 100%, 50%), -7px 396px hsl(2138.4, 100%, 50%), -5px 397px hsl(2143.8, 100%, 50%), -3px 398px hsl(2149.2, 100%, 50%), -1px 399px hsl(2154.6, 100%, 50%); font-size: 40px;"; console.log("%cExample %s", css, 'all code runs happy');

https://i.stack.imgur.com/q9nSf.jpg

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You can use a custom stylesheet to color your debugger. You can put this code in C:\Documents and Settings<User Name>\Local Settings\Application Data\Google\Chrome\User Data\Default\User StyleSheets\Custom.css if you are in WinXP, but the directory varies by OS.

.console-error-level .console-message-text{
    color: red;
}

.console-warning-level .console-message-text {
    color: orange;
}

.console-log-level .console-message-text {
    color:green;
}

---

Older versions of Chrome do not allow you to get console.log()s to show in a specific color programmatically, but calling console.error() will put a red X icon on error lines and make the text red, and console.warn() gets you a yellow ! icon.

You can then filter console entries with the All, Errors, Warnings, and Logs buttons beneath the console.

It turns out Firebug has supported custom CSS for console.logs since 2010 and Chrome support has been added as of Chrome 24.

console.log('%c Oh my heavens! ', 'background: #222; color: #bada55',
            'more text');

When %c appears anywhere in the first argument, the next argument is used as the CSS to style the console line. Further arguments are concatenated (as has always been the case).

---

I wrote template-colors-web https://github.com/icodeforlove/Console.js to allow us to do this a bit easier

console.log(c`red ${c`green ${'blue'.bold}.blue`}.green`.red);

The above would be extremely hard to do with the default console.log.

For a live interactive demo click here.

https://i.stack.imgur.com/9AQYW.png

---

Update:

I have written a JavaScript library last year for myself. It contains other features e.g verbosity for debug logs and also provides a download logs method that exports a log file. Have a look at the JS Logger library and its documentation.

I know It's a bit late to answer but as the OP asked to get custom color messages in console for different options. Everyone is passing the color style property in each console.log() statement which confuses the reader by creating complexity in the code and also harm the overall look & feel of the code.

What I suggest is to write a function with few predetermined colors (e.g success, error, info, warning, default colors) which will be applied on the basis of the parameter passed to the function.

It improves the readability and reduces the complexity in the code. It is too easy to maintain and further extend according to your needs.

Given below is a JavaScript function that you have to write once and than use it again and again.

function colorLog(message, color) {

    color = color || "black";

    switch (color) {
        case "success":  
             color = "Green"; 
             break;
        case "info":     
                color = "DodgerBlue";  
             break;
        case "error":   
             color = "Red";     
             break;
        case "warning":  
             color = "Orange";   
             break;
        default: 
             color = color;
    }

    console.log("%c" + message, "color:" + color);
}

Output:

https://i.stack.imgur.com/b0J3l.png

The default color is black and you don't have to pass any keyword as parameter in that case. In other cases, you should pass success, error, warning, or info keywords for desired results.

Here is working JSFiddle. See output in the browser's console.

---

I actually just found this by accident being curious with what would happen but you can actually use bash colouring flags to set the colour of an output in Chrome:

console.log('\x1b[36m Hello \x1b[34m Colored \x1b[35m World!');
console.log('\x1B[31mHello\x1B[34m World');
console.log('\x1b[43mHighlighted');

Output:

https://i.stack.imgur.com/7R5C9.png

https://i.stack.imgur.com/Mg29a.png

See this link for how colour flags work: https://misc.flogisoft.com/bash/tip_colors_and_formatting

Basically use the \x1b or \x1B in place of \e. eg. \x1b[31m and all text after that will be switched to the new colour.

I haven't tried this in any other browser though, but thought it worth mentioning.

---

colors = {
    reset: '\033[0m',

    //text color

    black: '\033[30m',
    red: '\033[31m',
    green: '\033[32m',
    yellow: '\033[33m',
    blue: '\033[34m',
    magenta: '\033[35m',
    cyan: '\033[36m',
    white: '\033[37m',

    //background color

    blackBg: '\033[40m',
    redBg: '\033[41m',
    greenBg: '\033[42m',
    yellowBg: '\033[43m',
    blueBg: '\033[44m',
    magentaBg: '\033[45m',
    cyanBg: '\033[46m',
    whiteBg: '\033[47m'
}

console.log('\033[31m this is red color on text');
console.log('\033[0m this is reset');
console.log('\033[41m this is red color on background');

---

Emoji

You can use colors for text as others mentioned in their answers to have colorful text with a background or foreground color.

But you can use emojis instead! for example, you can use⚠️ for warning messages and 🛑 for error messages.

Or simply use these notebooks as a color:

console.log('📕: error message'); console.log('📙: warning message'); console.log('📗: ok status message'); console.log('📘: action message'); console.log('📓: canceled status message'); console.log('📔: Or anything you like and want to recognize immediately by color');

🎁 Bonus:

This method also helps you to quickly scan and find logs directly in the source code.

But some Linux distribution default emoji font is not colorful by default and you may want to make them colorful, first.

How to open emoji panel?

mac os: control + command + space

windows: win + .

linux: control + . or control + ;

---

There are a series of inbuilt functions for coloring the console log:

//For pink background and red text
console.error("Hello World");  

//For yellow background and brown text
console.warn("Hello World");  

//For just a INFO symbol at the beginning of the text
console.info("Hello World");  

//for custom colored text
console.log('%cHello World','color:blue');
//here blue could be replaced by any color code

//for custom colored text with custom background text
console.log('%cHello World','background:red;color:#fff')

---

Yes just add %c sign before your message and the style followed by your message.

console.log('%c Hello World','color:red;border:1px solid dodgerblue');

If you are using node and want to color console in terminal then you can use escape sequences like

console.log('\x1b[33m%s\x1b[0m', 'hi!') 

will color console yellow, else you can use libraries like chalk to color console

const chalk = require('chalk') 
console.log(chalk.yellow('hi!')) 

---

Google has documented this https://developers.google.com/web/tools/chrome-devtools/console/console-write#styling_console_output_with_css

The CSS format specifier allows you to customize the display in the console. Start the string with the specifier and give the style you wish to apply as the second parameter.

One example:

console.log("%cThis will be formatted with large, blue text", "color: blue; font-size: x-large");

---

I've discovered that you can make logs with colors using ANSI color codes, what makes easier to find specific messages in debug. Try it:

console.log( "\u001b[1;31m Red message" );
console.log( "\u001b[1;32m Green message" );
console.log( "\u001b[1;33m Yellow message" );
console.log( "\u001b[1;34m Blue message" );
console.log( "\u001b[1;35m Purple message" );
console.log( "\u001b[1;36m Cyan message" );

---

template system, useful if you want to create colorful line text without creating full style for every block

var tpl = 'background-color:greenyellow; border:3px solid orange; font-size:18px; font-weight: bold;padding:3px 5px;color:';
console.log('%cNo #1' + '.%cRed Text' + '%cBlue Text', 
             tpl+'magenta', tpl+'red', tpl+'blue');

https://i.stack.imgur.com/4fvl1.jpg

---

I doubt that anyone will actually see it but I have a simple solution for those who want to mix several colors in the same line:

export enum Colors {
    Black = '\033[30m',
    Red = '\x1b[31m',
    Green = '\x1b[32m',
    Yellow = '\x1b[33m',
    Blue = '\033[34m',
    Magenta = '\033[35m',
    Cyan = '\033[36m',
    White = '\033[37m'
}


function color(text: string, color: color: Colors) {
    return `${color}${text}\x1b[0m`;
}


console.log(`This is ${color('green text', Colors.Green)} but this is black. This is red ${color('red', Colors.Red)} etc`);

---

Check this out:

Animation in console, plus CSS

(function() {
  var frame = 0;
  var frames = [
    "This",
    "is",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!",
    " ",
    "SPARTA!"
  ];
  var showNext = () => {
    console.clear();
    console.log(
      `%c `,
      "background: red; color: white; font-size: 15px; padding: 3px 41%;"
    );
    console.log(
      `%c ${frames[frame]}`,
      "background: red; color: white; font-size: 25px; padding: 3px 40%;"
    );
    console.log(
      `%c `,
      "background: red; color: white; font-size: 15px; padding: 3px 41%;"
    );
    setTimeout(
      showNext,
      frames[frame] === "SPARTA!" || frames[frame] === " " ? 100 : 1500
    );
    // next frame and loop
    frame++;
    if (frame >= frames.length) {
      frame = 0;
    }
  };
  showNext();
})();

https://jsfiddle.net/a8y3jhfL/

you can paste ASCII in each frame to watch an ASCII animation

---

If you want to be modern you can also use template literals here is a simple and complex example; Template literals let you use emojis, vars and way more cool stuff 😎

Simple

https://i.stack.imgur.com/h9QoD.png

Complex

https://i.stack.imgur.com/QcSJ9.png

Code

/* * Simple example */ console.log( `%c[line 42] | fooBar.js myFunc() -> YOU DEBUG MESSAGE HERE `, ` color:white; background-color:black; border-left: 1px solid yellow; padding: 4px;` ); /* * Complex example */ const path = `../this/goes/to/my/dir`; const line = 42; const ref = `myFunc()`; const message = `A FANCY DEBUG MESSAGE 💎💎💎 `; const styling = ` color:white; background-color:black; border-left: 1px solid yellow; padding: 8px; font-weight: 600; font-family: Courier; `; console.log( `%c ✨ F A N C Y - L O G G E R ✨`, `${styling} font-size: 16px; border-top: 1px solid yellow;` ); console.log( `%c Path: ${path} `, `${styling} font-size: 10px; font-weight: 100;` ); console.log( `%c Line: ${line}`, `${styling} font-size: 10px; font-weight: 100;` ); console.log( `%c Ref: ${ref} `, `${styling} font-size: 10px; font-weight: 100;` ); console.log( `%c Message: ${message} `, `${styling} font-size: 12px; border-bottom: 1px solid yellow;` );

---

from Chrome 60, they removed the facility of blue text color while writing console.info and does many much changes in console API.

if you write a string literal in the es6 pattern, using the backticks `` as the identifier (called as template string ) in console.log() then below way can colorize the console output.

console.log(`%cToday date=>%c${new Date()}`,`color:#F74C2F`, `color:green`);
// output :Today date (in red color) => Date (in green color)

---

To chain CSS3 styles which spans across multiple lines, you can do like this,

var styles = [
    'background: linear-gradient(#D33106, #571402)'
    , 'border: 1px solid #3E0E02'
    , 'color: white'
    , 'display: block'
    , 'text-shadow: 0 1px 0 rgba(0, 0, 0, 0.3)'
    , 'box-shadow: 0 1px 0 rgba(255, 255, 255, 0.4) inset, 0 5px 3px -5px rgba(0, 0, 0, 0.5), 0 -13px 5px -10px rgba(255, 255, 255, 0.4) inset'
    , 'line-height: 40px'
    , 'text-align: center'
    , 'font-weight: bold'
].join(';');

console.log('%c a spicy log message ?', styles);

Result

https://i.stack.imgur.com/6r7lF.png

Find more :- https://coderwall.com/p/fskzdw/colorful-console-log

Cheers.

---

You can try:

console.log("%cI am red %cI am green", "color: red", "color: green");

The output:

https://i.stack.imgur.com/Cb771.png

---

I recently wanted to solve for a similar issue and constructed a small function to color only keywords i cared about which were easily identifiable by surrounding curly braces {keyword}.

This worked like a charm:

var text = 'some text with some {special} formatting on this {keyword} and this {keyword}'
var splitText = text.split(' ');
var cssRules = [];
var styledText = '';
_.each(splitText, (split) => {
    if (/^\{/.test(split)) {
        cssRules.push('color:blue');
    } else {
        cssRules.push('color:inherit')
    }
    styledText += `%c${split} `
});
console.log(styledText , ...cssRules)

https://i.stack.imgur.com/M96j1.png

technically you could swap out the if statement with a switch/case statement to allow multiple stylings for different reasons

---

I wrote a reallllllllllllllllly simple plugin for myself several years ago:

To add to your page all you need to do is put this in the head:

<script src="https://jackcrane.github.io/static/cdn/jconsole.js" type="text/javascript">

Then in JS:

jconsole.color.red.log('hellllooo world');

The framework has code for:

jconsole.color.red.log();
jconsole.color.orange.log();
jconsole.color.yellow.log();
jconsole.color.green.log();
jconsole.color.blue.log();
jconsole.color.purple.log();
jconsole.color.teal.log();

as well as:

jconsole.css.log("hello world","color:red;");

for any other css. The above is designed with the following syntax:

jconsole.css.log(message to log,css code to style the logged message)

---

I create now the log-css.js https://codepen.io/luis7lobo9b/pen/QWyobwY

// log-css.js v1
const log = console.log.bind();
const css = function(item, color = '#fff', background = 'none', fontSize = '12px', fontWeight = 700, fontFamily) {
    return ['%c ' + item + ' ', 'color:' + color + ';background:' + background + ';font-size:' + fontSize + ';font-weight:' + fontWeight + (fontFamily ? ';font-family:' + fontFamily : '')];
};
// example
log(...css('Lorem ipsum dolor sit amet, consectetur adipisicing elit.', 'rebeccapurple', '#000', '14px'));

---

I wrote a npm module that gives one the possibility to pass:

Custom colors - to both text and background;

Prefixes - to help identify the source, like [MyFunction]

Types - like warning, success, info and other predefined message types

https://www.npmjs.com/package/console-log-plus

Output (with custom prefixes):

https://i.stack.imgur.com/Euxft.png

clp({
  type: 'ok',
  prefix: 'Okay',
  message: 'you bet'
});
clp({
  type: 'error',
  prefix: 'Ouch',
  message: 'you bet'
});
clp({
  type: 'warning',
  prefix: 'I told you',
  message: 'you bet'
});
clp({
  type: 'attention',
  prefix: 'Watch it!',
  message: 'you bet'
});
clp({
  type: 'success',
  prefix: 'Awesome!',
  message: 'you bet'
});
clp({
  type: 'info',
  prefix: 'FYI',
  message: 'you bet'
});
clp({
  type: 'default',
  prefix: 'No fun',
  message: 'you bet'
});

Output (without custom prefixes):

https://i.stack.imgur.com/b7Kh3.png

Input:

clp({
  type: 'ok',
  message: 'you bet'
});
clp({
  type: 'error',
  message: 'you bet'
});
clp({
  type: 'warning',
  message: 'you bet'
});
clp({
  type: 'attention',
  message: 'you bet'
});
clp({
  type: 'success',
  message: 'you bet'
});
clp({
  type: 'info',
  message: 'you bet'
});
clp({
  type: 'default',
  message: 'you bet'
});

To make sure the user won't render an invalid color, I wrote a color validator as well. It will validate colors by name, hex, rgb, rgba, hsl or hsla values

---

I created a package for the same. cslog

https://i.stack.imgur.com/lmeTS.png

Install it with

npm i cslog

Use It like this

import log from 'cslog'

log.h2("This is heading 2")
log.p("This is colored paragraph")
log.d(person, "Person Info")

You can give your custom colors as well. here

---

const coloring = fn => ({ background, color = 'white' }) => (...text) => fn(`%c${text.join('')}`, `color:${color};background:${background}`); const colors = { primary: '#007bff', success: '#28a745', warning: '#ffc107', danger: '#dc3545', info: '#17a2b8', }; const dir = (key = '', value = {}) => { logs.primary(`++++++++++++start:${key}++++++++++++++`); console.dir(value); logs.primary(`++++++++++++end:${key}++++++++++++++`); }; const logs = Object.keys(colors) .reduce((prev, curr) => ({ ...prev, [curr]: coloring(console.log)({ background: colors[curr] }) }), { dir }); logs.success('hello succes'); logs.warning('hello fail');

---

By default, there are few inbuilt console methods to display warnings, errors and normal console along with the specific icons and text colors.

console.log('console.log'); console.warn('console.warn'); console.error('console.error');

But If you still want to apply your own styles, You can use %c with the message and CSS style rules as a second parameter.

console.log('%cconsole.log', 'color: green;'); console.warn('%cconsole.warn', 'color: green;'); console.error('%cconsole.error', 'color: green;');

Note : While running the above code snippets, Kindly check the results in the browser console instead of snippet results.

---

Here's another approach (in Typescript), which overrides the console.log function and inspects the message passed in order to apply CSS formatting depending on a beginning token in the message. A benefit of this method is the callee's don't need to use some wrapper console.log function, they can stick to using vanilla console.log() and so if this override ever goes away the functionality will just revert to the default console.log:

// An example of disabling logging depending on environment:
const isLoggingEnabled = process.env.NODE_ENV !== 'production';

// Store the original logging function so we can trigger it later
const originalConsoleLog = console.log;

// Override logging to perform our own logic
console.log = (args: any) => {
    if (!isLoggingEnabled) {
        return;
    }

    // Define some tokens and their corresponding CSS
    const parsing = [
        {
            token: '[SUCCESS]',
            css: 'color: green; font-weight: bold;',
        },
        {
            token: '[ERROR]',
            css: 'color: red; font-weight: bold;',
        },
        {
            token: '[WARN]',
            css: 'color: orange; font-weight: bold;',
        },
        {
            token: '[DEBUG]',
            css: 'color: blue;',
        },
    ];

    // Currently only supports console.log(...) with a single string argument. 
    if (typeof args === 'string') {
        const message: string = args;
        let formattedArgs: string[] = [];
        for (let i = 0; i < parsing.length; i += 1) {
            const parser = parsing[i];
            if (args.startsWith(parser.token)) {
                formattedArgs = [`%c${message.substring(parser.token.length + 1, message.length)}`, parser.css];
                break;
            }
        }
        originalConsoleLog.apply(console, formattedArgs);
    } else {
        originalConsoleLog.apply(console, args);
    }
};

Example usage:

console.log('[ERROR] Something went wrong!');

Output:

https://i.stack.imgur.com/iMFP9.png

---

If you want to color your terminal console, then you can use npm package chalk

npm i chalk

https://i.stack.imgur.com/jZDYc.png

---