javascript字符串替换问题

Question

str.replace(/200/,'300').replace(/500/,'600')

Answer 1

var sre="http://localhost/shop/pbC1/C310/B288/p200t500.shtml";
sre=sre.replace(/200/,"300");
sre=sre.replace(/500/,"600");
alert(sre);

Answer 2

function bb(){
var oUrl = "http://localhost/shop/pbC1/C310/B288/p200t500.shtml";
var aa=oUrl.split("/");
var nUrl="";
for(i=0;i<7;i++){
nUrl+=aa[i]+"/";
}
nUrl+="p"+300+"t"+600+".shtml"
alert(nUrl);
this.location = nUrl;
}

Answer 3

 var sre="http://localhost/shop/pbC1/C310/B288/p200t500.shtml";
    sre=sre.replace(/200/,"300");
    sre=sre.replace(/500/,"600");
    alert(sre);