jquery remove class
$("button").click(function(){
$("p").removeClass("intro");
});
//Html code example:
<p class="red highlight">test1</p>
<p class="red highlight marked">test2</p>
<p class="red highlight">test3</p>
<p class="red highlight">test4</p>
// remove all highlight class from p tag
<script>
$( "p" ).removeClass( "highlight" )
</script>
// example $(element).removeClass( "myClass yourClass" )