I'd like to add a class 'hideme' to a empty div.

<div id="infocontent" class="grid_15 prefix_1">

     <h1 id="mainhead" class="grid_15 alpha omega" ></h1>
     <div id="infoinner" class="grid_13 prefix_1 suffix_1 alpha omega">


    <FORM ACTION="command.asp" METHOD="get" NAME="artForm">

   ....
   .....

I made this but something wrong.

$function(){
var contentid = $('#mainhead');
var content = contentid.html();
if 开发者_Go百科(content===''){
    contentid.addClass('hideme');
}
})

Update: Sorry it was empty h1.

Your <div> isn't empty; it contains all subsequent content until the end of <div id="infocontent">.

Close your tags!

always!

As other people have mentioned, your code can be simplified by using the :empty selector:

$('#mainhead:empty').addClass('hideme');

If the <div> is not empty, this selector will not match any elements, and the line will do nothing.

You can try this:

$function(){
var contentid = $('#mainhead');
var content = contentid.html();
if (contentid.is(':empty')==''){
    contentid.addClass('hideme');
}
})

Try this instead:

if (contentid.is(':empty')) {
  contentid.addClass('hideme');
}

Try,

   $("div:empty").addClass('hideme');