Focus is lost if validation fails on onblur event

I use JSF 1.2. I process onblur event with aj4:support and actionListener

<开发者_如何学Python;a4j:support event="onblur" reRender="panel1"  
      actionListener="#{bean.changeData}"  />

ActionListener validates inputted data. I would like focus to be returned if validation fails. How can I do it?

Set focus="componentId" in a4j:support.