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Zach Leatherman

Logical XOR in JavaScript

23 Mar 2007 Zach Leatherman

Of course there wouldn’t be an XOR function in JavaScript when I needed one. So I googled around and found an implementation at How To Create. But it only took two arguments. So I rolled my own supporting a variable number of arguments. In my personal stuff, I’ve put it into a Math library under the YAHOO namespace, and you can decide if you want to do that on your own.

function xor() {
var b = false;
for( var j = 0; j < arguments.length; j++ ) {
if( arguments[ j ] && !b ) b = true;
else if( arguments[ j ] && b ) return false;

return b;


xor( false, true ); // true
xor( true, true ); // false
xor( false, false, true, true, true, false, true, false ); // false
xor( false, false, false, true, false, false, false, false ); // true


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Come on, this is clearly incorrect. It is obvious from the code, no XOR implementation can return early (inside the loop), as the result of the XOR _always_ depends on all the input bits. This is the reason why it is used in checksums.

xor(1,0,1,1) should yield true, your implementation yields false.

Please remove the page or fix it.