[ilyas->]

function showSomething() {
    var a = $('.first-link-class');
    a[a.hasClass('handle') ? 'removeClass' : 'addClass']('handle')
}

Тоже не работает

<script>
	function showSomething() {
    var a = $('.first-link-class');
    a[a.hasClass('handle') ? 'removeClass' : 'addClass']('handle')
}

	</script>

<a href="#" onclick="showSomething()" class="first-link-class">Показать</a>

<a style="display: block; width: 140px; height: 35px; text-indent: -99999px; background: url(&quot;images/top.png&quot;) no-repeat scroll 0% 0% transparent; outline: medium none; position: absolute; z-index: 995; bottom: 0px; right: 108px; top: -35px;" class="handle" href="#" onclick="showSomething()"></a>