layui中怎么放大图片

第二部：javascript 代码

var ysw = 0;   //记录图片原始宽度var ysh = 0;   //记录图片原始高度layui.use('slider', function(){     var $ = layui.$      ,slider = layui.slider;     slider.render({            elem: '#slideys'             ,value: 0 //初始值             ,theme: '#1E9FFF'            ,step: 1 //步长            ,min: -10 //最小值            ,max: 10 //最大值            ,showstep: true //开启间隔点            ,change: function(value){                if(ysw ==0 || ysh == 0){                    return;                }                var pjw = ysw/20;                var pjh = ysh/20;                var img =  $("#dximg");  //图片ID                if(img!=null){                    var w = Math.round(ysw+(pjw*value));                    var h = Math.round(ysh+(pjh*value));                    $(img).css("width", w );                      $(img).css("height", h );                 }              }          });    });