canvas移动端常用技巧图片loading

<canvas id="myCanvas" width="200" height="100" style="border:1px solid #c3c3c3;">
Your browser does not support the canvas element.
</canvas>

<script type="text/javascript">

var c=document.getElementById("myCanvas");
var cxt=c.getContext("2d");
var img=new Image()
img.src="flower.png"
cxt.drawImage(img,0,0);

</script>

<section class="productul" id="productul">
     <ul>
         <li>
            <a href="#">
             <div class="triangle-topleft"></div>
             <span class="shuxing" data_url="productinfo.html">专属</span>
             <div class="leftimages fl"><canvas data-src="images/product/product1.png" ></canvas></div>
             <div class="productcontent fr">
                 <p class="ptitle pl10">标题</p>
                  <p class="pdes pl10">简介这里简介这里简介这里简介这里简介这里简介这里简介这里简介介这里简介</p>
                  <p class="pprice pl10">价格：<span class="green">￥5000</span></p>
             </div>
           </a>
         </li>
     </ul>    
</section>

img{width:100px;birder:0;}
canvas{width:100px;min-height:100px;background:#fff url("../images/loading.gif") center center no-repeat; background-size:15px auto; }

var imglength = $("#productul").find("canvas").length;
            if (imglength > 0) {
                $("#productul").find("canvas").each(function () {
                    var imgSrc = $(this).data("src");
                    var imageObj = new Image();
                    imageObj.canvs = $(this)[0];
                    var cvs = imageObj.canvs.getContext(‘2d‘);
                    if (cvs) {
                        imageObj.onload = function () {
                            imageObj.canvs.width = this.width;
                            imageObj.canvs.height = this.height;
                            cvs.drawImage(this, 0, 0);
                            $(imageObj.canvs).css("background-image", "none");
                        }
                        imageObj.src = imgSrc;
                    }
                })
            }
        }