var svgElement1 = iframeSvg.getElementById("VKnife1");
           svgElement1.onclick = function () {
               alert($(this)[0].href.baseVal)
               if ($(this)[0].href.baseVal == "#VKnife") {
                   $(this)[0].setAttributeNS('http://www.w3.org/1999/xlink', 'xlink:href', "#VKnife_Close");
                   //第二种方法
                   // $(this)[0].href.baseVal = "#unlocked";
               }
               else {
                   $(this)[0].setAttributeNS('http://www.w3.org/1999/xlink', 'xlink:href', "#VKnife");
               }
           }