Javascript: I have a form that searches jobs but my client wants to Require a field

I have a form that searches jobs but my client want to require something entered into the keyword area. Can someone help me with the js needed?
here is the code

<form action="{$GLOBALS.site_url}/search-results-jobs/" id="quickSearchForm">
		<input type="hidden" name="action" value="search" />
		<input type="hidden" name="listing_type[equal]" value="Job" />
		<fieldset>
			<div class="quickSearchInputName">[[Keywords*]]<br/>{search property=keywords}</div>
			<div class="quickSearchInputName">[[Industry]]<br/>{search property=JobCategory  template='list.tpl'}</div>
		</fieldset>
		<fieldset>

			<div class="quickSearchInputName">[[State]]<br/>{assign var="name" value='State.Name'}{search property=$name parent=Location country=$GLOBALS.settings.default_country template='list.tpl'}</div>
		</fieldset>
		<fieldset>
			<div class="quickSearchInputName">
				<a href="{$GLOBALS.site_url}/find-jobs/">* [[Advanced search]]</a>
				{if $acl->isAllowed('open_search_by_company_form')}
    				<br/>
    				<a href="{$GLOBALS.site_url}/browse-by-company/">* [[Search by Company]]</a>
				{/if}
			</div>
			<div class="quickSearchInputName"><input type="submit" value="[[Search Jobs]]"/></div>
		</fieldset>
	</form>