分享个人写的用于项目的全选和取消以及全选按钮随着子类选项的状态变化而变化

<div class="mui-content">  

                <form class="mui-input-group">  
                    <div class="mui-input-row mui-checkbox">  
                        <label>全部</label>  
                        <input id="selectall"  type="checkbox">  
                    </div>  
                    <div class="mui-input-row mui-checkbox">  
                        <label>四年级一班</label>  
                        <input name="subcheck"  type="checkbox">  
                    </div>  
                    <div class="mui-input-row mui-checkbox">  
                        <label>四年级二班</label>  
                        <input name="subcheck"  type="checkbox">  
                    </div>  
                    <div class="mui-input-row mui-checkbox">  
                        <label>四年级三班</label>  
                        <input name="subcheck"  type="checkbox">  
                    </div>  
                </form>  
            </div>

<script type="text/javascript">  
        var chkall=document.getElementById("selectall");  
        mui.plusReady(function(){  
            chkall.addEventListener("change",function(){  
                if(this.checked){  
                    mui("input[name='subcheck']").each(function(){  
                        this.checked=true;  

                    });  
                }else{  
                    mui("input[name='subcheck']").each(function(){  
                        this.checked=false;  

                    });  
                }  
            },false);  

            var cbknum=mui("input[name='subcheck']").length;  
             var chknum=0;      
            mui(".mui-input-group").on("change","input[name='subcheck']",function(){  

                if(this.checked)  
                {  
                    chknum++;  

                }else{  
                    chknum--;  
                }  
                if(cbknum==chknum){  

                    chkall.checked=true;  
                }else{  
                    chkall.checked=false;  

                }  

            });  

        });