function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

function MM_showHideLayers() { //v6.0
  var i,p,v,obj,args=MM_showHideLayers.arguments;
  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }
    obj.visibility=v; }
}


//去除左右两端的空格
function trim(s)  
{return  s.replace(/(^\s*)|(\s*$)/g,  "");} 

 
function $(id){
    return document.getElementById(id);
}

function TryThese(){
    for (i = 0; i < arguments.length; i++){
        try{
            return arguments[i]();
        }catch(e){}
    }
    return false;
}

function CreateXMLHTTP(){
    return TryThese(
        function() {return new ActiveXObject("Msxml2.XMLHTTP");},
        function() {return new ActiveXObject("Microsoft.XMLHTTP");},
        function() {return new XMLHttpRequest();}
    ) || false;
}

function SendRequest(url, param, method, echofun) {
    var xmlHTTP = CreateXMLHTTP();
    if (xmlHTTP){
        xmlHTTP.onreadystatechange = function()
        {
            if (xmlHTTP.readyState == 4 && xmlHTTP.status == 200){
                if (echofun!= null){
                    echofun(xmlHTTP.responseText);
                }
            }
        }
        xmlHTTP.open(method, url, true);
        xmlHTTP.setRequestHeader("Content-Length",param.length); 
        xmlHTTP.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded");
        xmlHTTP.send(encodeURI(param));    
    }else{
        NoXMLHTTP();
    }
}

function NoXMLHTTP(){
    alert("Sorry, your browser doesn't support XMLHTTP");
}
 
function checkbook(theform)
{  
   $("showaddmsg").style.display = 'block'
	
	if (trim(theform.content.value)=='')
	{  
	$("showaddmsg").innerHTML="内容不能为空";
		theform.content.focus();
		theform.content.value='';
		return false
	}
	if (trim(theform.username.value)=='')
	{  
	$("showaddmsg").innerHTML="姓名不能为空";
		theform.username.focus();
		theform.username.value='';
		return false
	}
	if (trim(theform.yzm.value)=='')
	{  
	$("showaddmsg").innerHTML="验证码不能为空";
		theform.yzm.focus();
		theform.yzm.value='';
		return false
	}
	var param;
	param="book.asp?action=save";
	param += "&username=" + escape(trim(theform.username.value));
	param += "&content=" + escape(trim(theform.content.value));
	param += "&yzm=" + escape(trim(theform.yzm.value));
 	$("showaddmsg").innerHTML ="提交中…";
    SendRequest(param, param, "POST", 
                function(responseText){
					var f= responseText.substring(0,1);
					if (f == "1"){
						$("showaddmsg").innerHTML =responseText.substring(1);
						setTimeout("$('showaddmsg').style.display = 'none';","3000");
						return false
					}
					else {
                        $("showaddmsg").innerHTML =responseText.substring(1);
						$("username").value='';
						$("content").value='';
						$("yzm").value='';
						location.href='?';
						
					}
                });
	return false
}