Hi,
I'm new to ajax4jsf and have some trouble with the onsubmit attribute in the a4j:support tag.
I have a text input field which includes an a4j:support tag. The characters entered by the user are displayed in an simple, ajax rendered output text tag.
Using the onSubmit attribute of the a4j:support tag I want to call a custom JavaScript function that checks the length of the text input field. If the length is less than 3 the function returns false to prevent the AJAX Request from being fired, but it is always sent!?

JavaScript function:
function checkLength() {
var length = document.getElementById("login_form:username").value.length;

if(length < 3) {
return false;
}
}


JSF:
<h:inputText binding="#{login.textInputUsername}"
readonly="false" id="username" size="30" value="#{login.username}">
<a4j:support event="onkeyup" reRender="repeater" onsubmit="checkLength()"/>
</h:inputText>


which is transformed into:
<input id="login_form:username" type="text" name="login_form:username" onkeyup="checkLength();A4J.AJAX.Submit('.....

The custom JavaScript function is called, and the length is also correct (thus less than 3 for the first two characters), but nevertheless the AJAX request is fired and the output text re-rendered.

I think it is only a small mistake, but I just can't find it.
Can anyone please help me!?

Regards
Jan