<form id="search_form" name="search_form" method="post">
<input type="text" name="username" />
</form>
<script type="text/javascript">
$(function() {
$('#btn').bind('click', function() {
document.search_form.action = 'admin/queryAll.do?pid=' + pid; //定义 action,并传参
$('#search_form').submit();
});
})
</script>