微信小程序自定义弹出模态框禁止底部滚动功能

<view class='fix_bottom'>
<view>分享</view>
<view>电话咨询</view>
<view class='active' bindtap="showDialogBtn">立即报名</view>
</view>

<!--模态框-->
<!-- 遮罩层 -->
<view class="modal-mask" bindtap="hideModal" catchtouchmove="preventTouchMove" wx:if="{{showModal}}"></view>

<view class="modal-dialog" wx:if="{{showModal}}">
<view class="modal-title">选择班次</view>
<view class="modal-content">
<view class="concent_list {{curindex==index? 'active':''}}" wx:for="{{concent_list}}" wx:for-index='index' data-index='{{index}}' bindtap='choose' data-name='{{item}}'>{{item}}</view>
</view>

<view class="modal-footer">
<view class="btn-cancel" bindtap="onCancel" data-status="cancel">取消</view>
<view class="btn-confirm" bindtap="onConfirm" data-status="confirm">确定</view>
</view>
</view>

.fix_bottom{
width: 100%;
height: 120rpx;
background: #fff;
position: fixed;
bottom: 0;
border-top: 1px solid #ccc;
display: flex;
}

.fix_bottom view{
width: 33.333%;
border-left: 1px solid #ccc;
line-height: 120rpx;
text-align: center;
font-size: 40rpx;
font-weight: bold;
}

.active{
color:#ffffff;
background: -moz-linear-gradient(left, #ff7b68, #ff5462);
 /* Safari 4-5, Chrome 1-9 */
 /* -webkit-gradient(, [, ]?, [, ]? [, ]*) */
 background: -webkit-gradient(linear,left,from(#ff7b68),to(#ff5462));
 /* Safari 5.1+, Chrome 10+ */
 background: -webkit-linear-gradient(left, #ff7b68, #ff5462);
 /* Opera 11.10+ */
 background: -o-linear-gradient(left, #ff7b68, #ff5462);
}

/* 模态框 */

.modal-mask {
width: 100%;
height: 100%;
position: fixed;
top: 0;
left: 0;
background: #000;
opacity: 0.5;
overflow: hidden;
z-index: 9000;
color: #fff;
}

.modal-dialog {
width: 540rpx;
overflow: hidden;
position: fixed;
top: 40%;
left: 0;
z-index: 9999;
background: #f9f9f9;
margin: -180rpx 105rpx;
border-radius: 36rpx;
}

.modal-title {
height: 100rpx;
line-height: 100rpx;
font-size: 36rpx;
color: #fff;
text-align: center;
background: -moz-linear-gradient(left, #ff7b68, #ff5462);
 /* Safari 4-5, Chrome 1-9 */
 /* -webkit-gradient(, [, ]?, [, ]? [, ]*) */
 background: -webkit-gradient(linear,left,from(#ff7b68),to(#ff5462));
 /* Safari 5.1+, Chrome 10+ */
 background: -webkit-linear-gradient(left, #ff7b68, #ff5462);
 /* Opera 11.10+ */
 background: -o-linear-gradient(left, #ff7b68, #ff5462);
border-bottom: 1px solid #ccc;

}

.modal-content {

}

.concent_list{
width: 100%;
height: 100rpx;
border-bottom: 1px solid #ccc;
line-height: 100rpx;
text-align: center;
}

.modal-footer {
display: flex;
flex-direction: row;
height: 86rpx;
font-size: 34rpx;
line-height: 86rpx;
}

.btn-cancel {
width: 50%;
color: #666;
text-align: center;
border-right: 1px solid #dedede;
}

.btn-confirm {
width: 50%;
color: #ec5300;
text-align: center;
}

var value='小学升初中'
Page({

/**
* 页面的初始数据
*/
data: {
showModal: false,
concent_list:['小学升初中','初一升初二','初二升初三','初中升高中'],
curindex:-1
},

/**
* 生命周期函数--监听页面加载
*/
onLoad: function (options) {

},

/**
* 生命周期函数--监听页面显示
*/
onShow: function () {
},

/**
* 弹窗
*/
showDialogBtn: function () {
this.setData({
showModal: true
})
},

/**
* 隐藏模态对话框
*/
hideModal: function () {
this.setData({
showModal: false
});
},

/**
* 对话框取消按钮点击事件
*/
onCancel: function () {
this.hideModal();
},
/**
* 对话框确认按钮点击事件
*/
onConfirm: function () {
this.hideModal();

})
},

choose:function(e){
var index=e.currentTarget.dataset.index
value = e.currentTarget.dataset.name
console.log(value)
this.setData({
curindex:index
})
}

})

<view class='diceng_wrap' style='position: {{position}}'>
底部所有内容内容内容
</view>