In a form, a SUBMIT (or button) is used to submit the code to two processing form pages separately.

<form onsubmit="aa(this);">
<input type="text" name="" value="test" /><input type="submit" value="submit" //>
</form>
<iframe src="" name="fA" frameborder="1" scrolling="no"></iframe>
<iframe src="" name="fB" frameborder="1" scrolling="no"></iframe>
<script type="text/javascript">
function aa(oForm){
="http://bbs.";
="fA"
();
="/bbs/";
="fB"
();
return false;
}
</script>