Javascript 檢查郵箱

function CheckEmail()
...{
    var obj=document.getElementById("checkEmail");
    var email=document.getElementById("TxtEmail").value;
    obj.className="Right";
    obj.innerHTML='正在檢查,請稍候...';
    if(email.length>0)
    ...{
        var Expression=/^w+([-+.']w+)*@w+([-.]w+)*.w+([-.]w+)*$/
        var regExp=new RegExp(Expression);
        if(regExp.test(email)==false)
        { 
            checkEmail="false1";
            SetCheckEmail(checkEmail);
            return;
        }
        else if(checking==true)
        {
            checkEmail="false2";
            SetCheckEmail(checkEmail);
            return;
        }
        else
        {
            checking=true;
            dos("e"+email);
        }
    }
    else
    {
        checkEmail="false"
        SetCheckEmail(checkEmail);
        return;
        
    }
}

function SetCheckEmail(arguments)
{
    var obj=document.getElementById("checkEmail");
    if(arguments=="false")
    {
        obj.className="Error";
        obj.innerHTML='請輸入Email地址';
    }
    else if(arguments=="false1")
    {
         obj.className="Error";
         obj.innerHTML='Email地址無效,請重新輸入';
    }
    else if(arguments=="false2")
    {
         obj.className="Error";
         obj.innerHTML='伺服器忙,請稍候...';
    }
    else if(arguments=="false3")
    {
        obj.className="Error";
        obj.innerHTML='Email地址已被註冊';
    }
    else if(arguments=="true")
    {
        obj.className="Right";
        obj.innerHTML='Email地址可以使用';
    }
}