i got a class,
div.domtab div{
clear:both;
width:auto;
background:#eee;
color:#000;
padding:1em 1.5em;
}
The reason the above answers are correct, is because this method specifies "Class" in it's name, implying that it is ASSUMED you are giving it a valid class name. Being as "." implies a class, this becomes a redundancy.
Thus, when using "removeClass" a "." should not be used.
You just missed out the line that is actually correct.
$('#tag1').removeClass('domtab');
The code above should do the trick.
Considering your markup is like:
<div class="domtab">
...
<div id="tag1"></div>
...
</div>
You can remove the class by
$('#tag1').closest('.domtab').removeClass('domtab');
try $('#tag1').removeClass('domtab');