基于jqury的数秒后自动提交form

<script language='javascript'>
<!--
$(document).ready(function(){
// #formDownload ajaxForm
$('#formDownload').ajaxForm({
target: '#formDownloadWindows', success: function() {
}
});

});

function jump(count,formId) {
window.setTimeout(function(){
count--;
if(count > 0) {
$('#jumpNum').html(count);
jump(count,str);
} else {
$(str).submit();
}
}, 1000);
}

//-->
</script>

<form action="/action/download" method="post" id="formDownload">
Wait <span id="jumpNum"></span> seconds
<input type="button" onclick="jump(30,"#formDownload");" />
</form>