Convert rgb color to hex color

If you have written HTML file, you must know that how to assign color to DOM element. You just need to assign CSS style to

DOM element like

＜span style="color:#ff0000"＞This is text＜/span＞

It is very simple. But, we may want to change the color

by Javascript like color picker. What's the problem? You may get the "rgb(255, 0, 0)" color value by Javascript.

Then, you have to convert rgb to hex color or convert hex to rgb color. The following is simple code.

rgb to hex

function rgb2hex(rgb){
   var hexDigits = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f");
   var hex = function(x){
       return isNaN(x) ? "00" : hexDigits[(x - x % 16) / 16] + hexDigits[x % 16];
   };
   var tmp = rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
   var color = hex(tmp[1]) + hex(tmp[2]) + hex(tmp[3]);
   return color;
}

hex to rgb

function hex2rgb(v){
   if (/^[0-9A-F]{3}$|^[0-9A-F]{6}$/.test(v.toUpperCase())) {
       if (v.length == 3) {
           v = v.match(/[0-9A-F]/g);
           v = v[0] + v[0] + v[1] + v[1] + v[2] + v[2];
           this.value = v;
       }
      
       var r = parseInt(v.substr(0, 2), 16);
       var g = parseInt(v.substr(2, 2), 16);
       var b = parseInt(v.substr(4, 2), 16);
       return [r, g, b].join(',');
   }
   return v;
}

Result

var input = $(this).css('color'); // rgb(255,0,0)

var hex = rgb2hex(input); //ff0000
var rgb = hex2rgb(hex);   //255,0,0

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