H5area的热区锚点随着图片的尺寸而变化

<area shape="rect" coords="338,308,609,589" >

<img id="pic" src="pic.jpg" alt="" usemap="#Map" width="1920" height="1080" />


<area shape="rect" coords="338,308,609,589" href="/" class="box" target="_blank"/>


var picw = $("#pic").width();
var pich = $("#pic").height();
var x1 = parseInt(picw*0.1820);
var y1 = parseInt(pich*0.2955);
var x2 = parseInt(picw*0.3280);
var y2 = parseInt(pich*0.5645);
$(".box").attr("coords",'"'+x1+','+y1+','+x2+','+y2+'"')