<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script><script type="text/javascript">$(function(){    $("#form").submit(function(){//表单提交:复选框取值        var obj=$(‘input:checkbox[name="aaa"]:checked‘);        alert("长度: "+obj.length);        obj.each(function(){            var s=$(this).val();            alert(s);        });        return false;    });});</script><form method="post" action="" id="form">    <input type="checkbox" name="aaa" value="1" checked>    <input type="checkbox" name="aaa" value="2">    <input type="checkbox" name="aaa" value="3">    <input type="submit"></form>

<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script><script type="text/javascript">$(function(){    $("#form").submit(function(){//表单提交：单选框取值        var aaa=$(‘input:radio[name="aaa"]:checked‘).val();        alert(aaa);        return false;    });});</script><form method="post" action="" id="form">    <input type="radio" name="aaa" value="1" checked>    <input type="radio" name="aaa" value="2">    <input type="radio" name="aaa" value="3">    <input type="submit"></form>

<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script><script type="text/javascript">$(function(){    $("#check_all").click(function(){            var a=$(this)[0].checked;            //alert( typeof a);            var inputs = document.getElementsByTagName("input");            for(var i=0; i< inputs.length; i++){                if(inputs[i].type == "checkbox"){                    inputs[i].checked = a;                 }            }    });});</script><input type="checkbox" name="" id="check_all">选择所有<hr><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br><input type="checkbox" name=""><br>