layui扩展上传组件模拟进度条的方法

<div id="uploadPatchForm"  class="roundRect"> 
  <div id="uploadLoadingDiv">
    <div class="layui-progress" lay-showpercent="true" lay-filter="demo" >
	  <div class="layui-progress-bar layui-bg-red" lay-percent="0%"></div>
	</div>
  </div>
  <form class="layui-form" enctype="multipart/form-data">
	<div class="layui-form-item layui-upload">
	  <span id="uploadName" ></span>
	  <button type="button" class="layui-btn layui-btn-normal" id="test8" >
        <i class="layui-icon"></i>
      </button>
	</div>
	<div class="layui-form-item">
	  <div class="layui-input-block">
	    <input type="radio" name="upgradeType" value="30011001" title="手动升级">
	    <input type="radio" name="upgradeType" value="30011002" title="自动升级" checked>
	  </div>
	</div>
	<div class="layui-form-item">
	  <div class="layui-input-block">
		<a class="roundCornerDiv aLineGray" href="javascript:layer.closeAll();" rel="external nofollow" >
		  <span type="reset" class="ButtonText popupCloseBtn">取消</span>
		</a>
		<a class="roundCornerDiv aLineOrange">
	      <button class="ButtonText submitBtn" type="button" id="test9">立即提交</button>
	    </a> 
	  </div>
	</div>
  </form>
</div>

layui.use(['upload','element','layer'], function(){
	var upload = layui.upload,element = layui.element,layer = layui.layer;
	var timer;//定义一个计时器
	//选完文件后不自动上传
	upload.render({
	  elem: '#test8'
	  ,url: 'upload'
	  ,async: false
	  ,method: 'post'
	  ,data: {
	    upgradeType: function(){
		  return $("input[name='upgradeType']:checked").val();//额外传递的参数
	    }
	  }
	  ,auto: false
	  ,accept: 'file' //普通文件
	  ,exts: 'zip' //只允许上传压缩文件
	  ,field:'uploadFile'
	  ,bindAction: '#test9'
	  ,choose: function(obj){//这里的作用是截取上传文件名称并显示
		var uploadFileInput=$(".layui-upload-file").val();
		var uploadFileName=uploadFileInput.split("\\");
		$("#uploadName").text(uploadFileName[uploadFileName.length-1]);
	  }
	  ,before: function(obj){ //obj参数包含的信息，跟choose回调完全一致
		layer.load(); //上传loading
		var n = 0; 
		timer = setInterval(function(){//按照时间随机生成一个小于95的进度，具体数值可以自己调整
		  n = n + Math.random()*10|0; 
		  if(n>95){
			n = 95;
			clearInterval(timer);
		  }
		  element.progress('demo', n+'%');
		}, 50+Math.random()*100);
	  }
	  ,done: function(res){
		clearInterval(timer);
		element.progress('demo', '100%');//一成功就把进度条置为100%
		layer.closeAll(); layer.msg('上传成功');}  ,error: function(index, upload){element.progress('demo', '0%');layer.closeAll(); //关闭所有层layer.msg('上传更新包失败');  }});});