I have the following code snippet:

{code:xml}
<h:inputText id="txtPercReqAmount" maxlength="6" style="width:75px;text-align:right;" value="#{pib.reservedPercentage}">
          <a4j:support event="onchange" ajaxSingle="true" action="#{requestForm.onReservedPercentageChange(pib)}" reRender="txtReqAmount,txtBudget"/>
          <f:validator validatorId="validatePercentage"/>
</h:inputText>
{code}

I'd like to fire the validation only on the input change event and not on form submit. Is it possible with <f:validator> or can you suggest another simple solution?