var body='<table width=100%>' +
		'<form name=GBForm method=post action=addPost.asp>' +
		'<tr>' +
		'  <td><img src=img/index/3.jpg width=100% height=43></td>' +
		'</tr>' +
		'<tr>' +
		'  <td align=center> ' +
		'	<p> ' +
		'	  <textarea name=GBContent rows=3></textarea>' +
		'	  <br>' +
		'	  <input type=text name=GBMail  value=请输入你的E-mail地址 onclick="chknull(this);">' +
		'		<input type=hidden name=act value=add>' +
		'	  <input type=button name=Submit value=提交 onclick="return checkdata();">' +
		'	</p>' +
		'	</td>' +
		'</tr>' +
		'  </form>' +
		'</table>';

document.write(body);


function checkdata()
{
	if(Jtrim(GBForm.GBContent.value).length <= 0)
	{
		alert("留言内容不能为空!");
		GBForm.GBContent.focus();
		return false;
	}
	if(!isEmail(GBForm.GBMail.value))
	{
		alert("请输入正确的电子邮件地址!");
		GBForm.GBMail.focus();
		return false;
	}
	GBForm.submit();
	return true;	
}

function chknull(the)
{
	the.value='';
}

function Jtrim(str)
{
        var i = 0;
        var len = str.length;
        if ( str == "" ) return( str );
        j = len -1;
        flagbegin = true;
        flagend = true;
        while ( flagbegin == true && i< len)
        {
           if ( str.charAt(i) == " " )
                {
                  i=i+1;
                  flagbegin=true;
                }
                else
                {
                        flagbegin=false;
                }
        }

        while  (flagend== true && j>=0)
        {
            if (str.charAt(j)==" ")
                {
                        j=j-1;
                        flagend=true;
                }
                else
                {
                        flagend=false;
                }
        }

        if ( i > j ) return ("")

        trimstr = str.substring(i,j+1);
        return trimstr;
}

function isEmail(s)
{
        if (s.length > 100)
                return false;
         var regu = "^(([0-9a-zA-Z]+)|([0-9a-zA-Z]+[_.0-9a-zA-Z-]*[_.0-9a-zA-Z]+))@([a-zA-Z0-9-]+[.])+([a-zA-Z]{2}|net|NET|com|COM|gov|GOV|mil|MIL|org|ORG|edu|EDU|int|INT)$";
         var re = new RegExp(regu);
         if (s.search(re) != -1)
              return true;
          else 
             return false;
}