js中判断两个数组中是否有相同的值

判断两个数组中是否有相同的值

        $ = [1,2,3,4,5];
        $[1,2,3]
	    for (var i = 0; i < $; i++) {
	        var obj = $[i];
	        var num = ;
	         var isExist= false;
	        for (var j = 0; j < $; j++) {
	            var aj = $[j];
	            var n = ;
	            if (n == num) {
	               isExist=true;
	               break;
	            }
	        }
	        return isExist;
	    }