function indexOf(list, element, comparator) {
			for (var i=0,item; item=list[i]; i++) {
				if (equals(item, element, comparator)) {
					return i;
				}
			}
			return -1;
		}
// returns index of given element in given list, using given comparator
returns index of given element in given list, using given comparator
returns index of given element in given list using given comparator
function indexOf(list, element, comparator) {
			for (var i=0,item; item=list[i]; i++) {
				if (equals(item, element, comparator)) {
					return i;
				}
			}
			return -1;
		}
function indexOf ( list , element , comparator ) { for ( var i = 0 , item ; item = list [ i ] ; i ++ ) { if ( equals ( item , element , comparator ) ) { return i ; } } return - 1 ; }
returns index of given element in given list, using given comparator
returns index of given element in given list using given comparator