javascript - RGB to Hex and Hex to RGB -

how convert colors in rgb format hex format , vice versa?

for example, convert '#0080c0' (0, 128, 192).

the following rgb hex conversion , add required 0 padding:

function componenttohex(c) {     var hex = c.tostring(16);     return hex.length == 1 ? "0" + hex : hex; }  function rgbtohex(r, g, b) {     return "#" + componenttohex(r) + componenttohex(g) + componenttohex(b); }  alert( rgbtohex(0, 51, 255) ); // #0033ff 

converting other way:

function hextorgb(hex) {     var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);     return result ? {         r: parseint(result[1], 16),         g: parseint(result[2], 16),         b: parseint(result[3], 16)     } : null; }  alert( hextorgb("#0033ff").g ); // "51"; 

finally, alternative version of rgbtohex(), discussed in @casablanca's answer , suggested in comments @cwolves:

function rgbtohex(r, g, b) {     return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).tostring(16).slice(1); } 

update 3 december 2012

here's version of hextorgb() parses shorthand hex triplet such "#03f":

function hextorgb(hex) {     // expand shorthand form (e.g. "03f") full form (e.g. "0033ff")     var shorthandregex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;     hex = hex.replace(shorthandregex, function(m, r, g, b) {         return r + r + g + g + b + b;     });      var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);     return result ? {         r: parseint(result[1], 16),         g: parseint(result[2], 16),         b: parseint(result[3], 16)     } : null; }  alert( hextorgb("#0033ff").g ); // "51"; alert( hextorgb("#03f").g ); // "51";