checkbox全选

HTML代码

        <input type="checkbox" id="checkAll" value="checkAll">全选<input type="checkbox" name="checkBtn" id="xz1" value="xz2">北京<br><input type="checkbox" name="checkBtn" id="xz2" value="xz2">上海<br><input type="checkbox" name="checkBtn" id="xz3" value="xz3">天津<br>

控制全选JS

             $("#checkAll").click(function(){if(this.checked){$("input[name=checkBtn]").attr("checked",true);}else{$("input[name=checkBtn]").attr("checked",false);}});$(":checkbox[name=checkBtn]").click(function(){var all = $("input[name=checkBtn]").length;var aa =  $("input[name=checkBtn]:checked").length;if(all==aa){$("#checkAll").attr("checked",true);}else{$("#checkAll").attr("checked",false);}});