Js Sort Works In Firefox But Not Ie - Can't Work Out Why

I have a line in a javascript function that sort an array of objects based on the order of another array of strings. This is working in firefox but not in IE and i don't know why.

Solution 1:

First, there's no indexOfmethod of Array in IE <= 8. You'll need to write your own. Second, the comparison function passed to the sort() method of an Array should return a number rather than a Boolean.

var indexOf = (typeof Array.prototype.indexOf == "function") ?
    function(arr, val) {
        return arr.indexOf(val);
    } :

    function(arr, val) {
        for (var i = 0, len = arr.length; i < len; ++i) {
            if (typeof arr[i] != "undefined" && arr[i] === val) {
                return i;
            }
        }
        return -1;
    };

csubSorted = csub.sort(function(a,b){
    return indexOf(originalData, a.value) - indexOf(originalData, b.value);
});