function test() {
var a='';
for (var i=0; i<100; i++) {
a+='abcdefghij';
}
before = new Date();
var loops = 10000;
for (var i=0; i<loops; i++) {
a.substring(234,567);
}
after = new Date();
tim = (after-before);
result(time);
}

Time: