String.prototype.format = function(args) {
var result = this;
if (arguments.length > 0) {
if (arguments.length == 1 && typeof (args) == "object") {
for (var key in args) {
if (args[key] != undefined) {
var reg = new RegExp("({" + key + "})", "g");
result = result.replace(reg, args[key]);
}
}
}
else {
for (var i = 0; i < arguments.length; i++) {
if (arguments[i] != undefined) {
//var reg = new RegExp("({[" + i + "]})", "g");//这个在索引大于9时会有问题，谢谢何以笙箫的指出
var reg = new RegExp("({)" + i + "(})", "g");
result = result.replace(reg, arguments[i]);
}
}
}
}
return result;
}
String.format = function () {
if (arguments.length == 0)
return null;
var str = arguments[0];
for (var i = 1; i < arguments.length; i++) {
var re = new RegExp('\\{' + (i - 1) + '\\}', 'gm');
str = str.replace(re, arguments[i]);
}
return str;
}//两种调用方式
var template1="我是{0}，今年{1}了";
var template2="我是{name}，今年{age}了";
var result1=template1.format("loogn",22);
var result2=template2.format({name:"loogn",age:22});
//两个结果都是"我是loogn，今年22了"
var a = "I Love {0}, and You Love {1},Where are {0}! {4}";
alert(String.format(a, "You","Me"));
alert(a.format("You","Me"));