var W = screen.width;//取得屏幕分辨率宽度
var H = screen.height;//取得屏幕分辨率高度

function M(id){
    return document.getElementById(id);//用M()方法代替document.getElementById(id)
}
function MC(t){
   return document.createElement(t);//用MC()方法代替document.createElement(t)
};
//判断浏览器是否为IE
function isIE(){
      return (document.all && window.ActiveXObject && !window.opera) ? true : false;
} 
//取得页面的高宽
function getBodySize(){
   var bodySize = [];
   with(document.documentElement) {
    bodySize[0] = (scrollWidth>clientWidth)?scrollWidth:clientWidth;//如果滚动条的宽度大于页面的宽度，取得滚动条的宽度，否则取页面宽度
    bodySize[1] = (scrollHeight>clientHeight)?scrollHeight:clientHeight;//如果滚动条的高度大于页面的高度，取得滚动条的高度，否则取高度
   }
   return bodySize;
}
//创建遮盖层
function popCoverDiv(){
   if (M("cover_div")) {
   //如果存在遮盖层，则让其显示 
    M("cover_div").style.display = 'block';
   } else {
   //否则创建遮盖层
    var coverDiv = MC('div');
    document.body.appendChild(coverDiv);
    coverDiv.id = 'cover_div';
    with(coverDiv.style) {
     position = 'absolute';
     background = '#CCCCCC';
     left = '0px';
     top = '0px';
     var bodySize = getBodySize();
     width = bodySize[0] + 'px'
     height = bodySize[1] + 'px';
     zIndex = 0;
     if (isIE()) {
      filter = "Alpha(Opacity=60)";//IE逆境
     } else {
      opacity = 0.6;
     }
    }
   }
}




//让登陆层显示为块 
    function showLogin()
    {
                var login=M("login");
            login.style.display = "block";
        }

//设置DIV层的样式
function change(){
          var login = M("login");
      login.style.position = "absolute";
      login.style.border = "1px solid #CCCCCC";
      login.style.background ="#EBF4FB";
      var i=0;
          var bodySize = getBodySize();
      login.style.left = 500+"px";
      login.style.top = 200+"px";
      login.style.width =      i*i*2.5 + "px";
      login.style.height = i*i*1.5 + "px";
     
      popChange(i);
}
//让DIV层大小循环增大
function popChange(i){
      var login = M("login");
          var bodySize = getBodySize();
      login.style.left = 500+"px";
      login.style.top = 200+"px";
      login.style.width =      i*i*2.5 + "px";
      login.style.height = i*i*1.5+ "px";
      if(i<=10){
           i++;
           setTimeout("popChange("+i+")",10);//设置超时10毫秒
      }
}
//打开DIV层
function open()
{
        change();
        showLogin();
        popCoverDiv()
        void(0);//不进行任何操作,如：<a href="#">aaa</a>
}
//关闭DIV层
function close(){
         M('login').style.display = 'none';
         M("cover_div").style.display = 'none';
        void(0);
}


 function checkdl2()
 {
  if(this.formdl.username.value=="")
  {
    alert('用户名不能为空！');
	this.formdl.username.focus();
	return false;
  }
  else
  {
  if (this.formdl.username.value.length < 2 || this.formdl.username.value.length > 10 ) 
{
	alert('用户名长度必须为2--10位');
	this.formdl.username.focus();
	return false;
}
var check = /^[A-Za-z0-9\_]*$/;
if (!check.test(this.formdl.username.value))
{
	alert("用户名" + "必须为英文,数字和下划线");
	this.formdl.username.focus();
	return false;
}
}
  if(this.formdl.password.value=="")
  {
   alert('密码不能为空');
   this.formdl.password.focus();
   return false;
  }
  else
  {
    var check = /^[A-Za-z0-9]*$/;
if (!check.test(this.formdl.password.value))
{
	alert("密码" + "必须为英文,数字");
	this.formdl.password.focus();
	return false;
}
    if(this.formdl.password.value.length<6||this.formdl.password.value.length>20)
	{
	 alert('密码长度必须在6~20个字符');
	 this.formdl.password.focus();
	 return false;
	}
  }

   }



document.write('<div id="login">')
document.write('<div  style="background:#88B4FB; width:50%; text-align:left; float:left;">&nbsp;&nbsp;<b>彼得教育登录</b></div><div  style="background:#88B4FB; width:50%; text-align:right; float:left;"><a href="javascript:close();"><font color=#ffffff>关闭</font></a>&nbsp;&nbsp;&nbsp;&nbsp;</div>')
document.write('<form name="formdl" method="post" action="checklogin.asp">')
  document.write('<div  style=" width:100%; padding:20px 10px 5px 10px; text-align:left; float:left; height:30px;">&nbsp;&nbsp;<b>用户名：</b><input name="username" type="text" size="25" id="username"  value="" maxlength="20" /></div>')

  document.write('<div  style=" width:100%; padding:5px 10px 5px 10px; text-align:left; float:left; height:30px;">&nbsp;&nbsp;<b>密 &nbsp;码：</b><input name="password"  type="password" size="27" value="" maxlength="20" /><input name="yzm"  type="hidden"   value="bideedu"  size="20"/></div>')
  
  document.write('<div  style=" width:100%; padding:5px 10px 5px 10px; text-align:center;float:left;">')
   document.write('<input  type="submit" value="登 录" onClick="return checkdl2();" />&nbsp;&nbsp;&nbsp;<input name="cz" type="reset" value="重置" /></div>')
  document.write(' </form>')
document.write('</div>')