$('#tag-id').removeAttr('style');
$("p").removeClass( "myClass yourClass" )
$("div").removeClass("important");
addClass() - Adds one or more classes to the selected elements
removeClass() - Removes one or more classes from the selected elements
toggleClass() - Toggles between adding/removing classes from the selected elements
css() - Sets or returns the style attribute
$("#id").css({ 'background-color' : '', 'opacity' : '' });
$(".class").css({ 'background-color' : '', 'opacity' : '' });
//You can remove css by the above.
$("body").removeAttr("style");
$("#id .class").css({ 'background-color' : '' });
/*
As mentioned in the jquery documentation:
Setting the value of a style property to an empty string
removes that property from an element
if it has already been directly applied
e.g. $('#mydiv').css('color', '')
*/
$('.tag-class').removeAttr('style');
$.css("background-color", "");
$("#id").css("background-color","");
$("#id").css("opacity","");