测试JavaScript字符串处理性能的代码

var oldtime = new Date().getTime();
var str = [];
for(i=0;i<100000;i++)
{
str.push(abcabcabcabcabcabcabcabcabcabcabcabc);
}
var newtime = new Date().getTime();
var joinTime = (newtime - oldtime);

var oldtime = new Date().getTime();
var str=;
for(i=0;i<100000;i++)
{
str += abcabcabcabcabcabcabcabcabcabcabcabc;
}
var newtime = new Date().getTime();
var concatTime = (newtime - oldtime);

alert("join / concat: " + (joinTime * 1.0 / concatTime));