prevent ajax form submit

[Carlos Gómez Montiel]

Hi there

How can I prevent ajax form's event submit when the user clicks a submit
button?
I need to prevent the event for show an confirm dialog before it will be
submited.

My form:

<t:form t:id='form1' t:zone='zone1'>
    <t:submit value="send"/>
</t:form>

<t:zone t:id='zone1' id='zone1'>
</t:zone>

Thanks in advance