拖动放大缩小图片截图js代码

一款原生JS图片截图选取特效,拖动放大缩小图片截图js代码,网页图片截图代码。
js代码
<script language="javascript" type="text/javascript"> function ShowValue(x,y,h,w,i) { document.getElementById("Demo" + i + "_Left").innerHTML = x; document.getElementById("Demo" + i + "_Top").innerHTML = y; document.getElementById("Demo" + i + "_Width").innerHTML = w; document.getElementById("Demo" + i + "_Height").innerHTML = h; } </script>