String.prototype.trim = function() {
	return this.replace(/^\s*|\s*$/g,"");
}

/*** 检查是否由数字字母和下划线组成 ***/ 

String.prototype.isAlpha = function() { 
return (this.replace(/\w/g, "").length == 0); 
} 

/*** 检查是否为数 ***/ 

String.prototype.isNumber = function() { 
var s = this.Trim(); 
return (s.search(/^[+-]?[0-9.]*$/) >= 0); 
} 

/*** 返回字节数 ***/ 

String.prototype.lenb = function() { 
return this.replace(/[^\x00-\xff]/g,"**").length; 
} 


/*** 检查是否包含汉字 ***/ 

String.prototype.isInChinese = function() { 
return (this.length != this.replace(/[^\x00-\xff]/g,"**").length); 
} 

function getRadomNum(){
	var rad  = Math.random()*100000+" ";
	return rad.substring(0,3);
}

function isEmailValid(e) {
	var ok = "1234567890qwertyuiop[]asdfghjklzxcvbnm.+@-_QWERTYUIOPASDFGHJKLZXCVBNM";
	for(var i=0; i<e.length; i++){
		if (ok.indexOf(e.charAt(i))<0) {
			return false;
		}
	}
	if (document.images) {
		var re = /(@.*@)|(\.\.)|(^\.)|(^@)|(@$)|(\.$)|(@\.)/;
		var re_two = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,8}|[0-9]{1,3})(\]?)$/;
		if (!e.match(re) && e.match(re_two)) {
			return -1;
		}
	}
}

/*** 验证是否为合法url ***/ 
function IsURL(str_url){
    var strRegex = "^[a-zA-z]+://(\\w+(-\\w+)*)(\\.(\\w+(-\\w+)*))*(\\?\\S*)?$"; 
          var re=new RegExp(strRegex); 
			//re.test()
          if (re.test(str_url)){
              return (true); 
          }else{ 
              return (false); 
          }
      }