js format用法

[lcgyh]

var code='123'
 	var frstcode='ph001'
 	var aftercode='ph002'
 	var str='修改商品编码%s由%s改为%s'
 	
 	String.prototype.format = function() {  
	 	if(arguments.length == 0) return this;  
	 	var param = arguments[0];  
	 	var s = this;  
	 	if(typeof(param) == 'object') {  
	  	for(var key in param)  
	   		s = s.replace(new RegExp("\\{" + key + "\\}", "g"), param[key]);  
	  		return s;  
	 	} else {  
			for(var i = 0; i < arguments.length; i++){
			  	s = s.replace(new RegExp("%s"), arguments[i]); 
			}  
	   		return s;  
	 	}  
	}

	var str1=str.format(code,frstcode,aftercode)
	console.log(str1)   //修改商品编码123由ph001改为ph002