Where would I use a bitwise operator in JavaScript?

javascript bitwise-operators
James picture James · Mar 17, 2009 · Viewed 31.8k times · Source

I've read 'what are bitwise operators?', so I know what bitwise operators are but I'm still not clear on how one might use them. Can anyone offer any real-world examples of where a bitwise operator would be useful in JavaScript?

Thanks.

Edit:

Just digging into the jQuery source I've found a couple of places where bitwise operators are used, for example: (only the & operator)

// Line 2756:
event.which = (event.button & 1 ? 1 : ( event.button & 2 ? 3 : ( event.button & 4 ? 2 : 0 ) ));

// Line 2101
var ret = a.compareDocumentPosition(b) & 4 ? -1 : a === b ? 0 : 1;

Answer

Mark picture Mark · Mar 17, 2009

Example:

Parses hexadecimal value to get RGB color values.

var hex = 'ffaadd';
var rgb = parseInt(hex, 16); // rgb is 16755421


var red   = (rgb >> 16) & 0xFF; // returns 255
var green = (rgb >> 8) & 0xFF;  // 170
var blue  = rgb & 0xFF;     // 221

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