Parameter passing using Javascript+actionFunction in visualforce

In visualforce, there is a method for passing parameters from visualforce page to controller using javascript and actionFunction. Here is the example;

/*JavaScript*/

<script type="text/javascript">
function doSave(date) {
    paraFunction(document.getElementById(date).value);
}
</script>

/*Action Function*/

<apex:actionFunction name="paraFunction" action="{!saveInterviewDate}" rerender="view">     
     <apex:param id="aname" name="interviewDate" value="" />
 </apex:actionFunction>

/*Call the javaScript from here*/

<apex:commandLink onclick="doSave('{!$Component.interviewDate}');">               
                       <apex:commandButton value="Save"/>
                   </apex:commandLink>

/*get the parameter in controller*/

String interviewdate=Apexpages.currentPage().getParameters().get('interviewDate');