专门方便用来查找表单元素

<script type="text/javascript">
    $(function() {
        //获取所有的input、button、select、textarea
        console.log($(":input"));
        //选取所有的单行文本框 (type=text)
        console.log($(":text"));
        console.log($(":password"));
        console.log($(":radio"));
        console.log($(":checkbox"));
        console.log($(":submit"));
        console.log($(":button"));        
    });
</script>