javascript注册用户常用正则验证代码

var re = /^[_a-zA-Z0-9-.]+@([-_a-zA-Z0-9]+.)+[a-zA-Z0-9]{2,3}$/;

if (!thisinput.value.match(re))
 {
  regemailinfo.className = "show err";
  regemailinfo.innerHTML = "输入不符合规范";
 }

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

//Count string byte number, return integer
String.prototype.ByteCount = function()
{
 txt = this.replace(/(<.*?>)/ig,"");
 txt = txt.replace(/([u0391-uFFE5])/ig, "11");
 var count = txt.length;
 return count;
}

var re = /^[a-zA-Z1-9_]{6,20}$/;
       if (!thisinput.value.match(re))
 {
  reguserinfo.className = "show err";
  reguserinfo.innerHTML = "输入不符合规范";
 }