打印时mm转像素px,像素px转mm

function px2pm(d) {
var iswindow = /windows|win32/i.test(navigator.userAgent);
if (iswindow) {
return Math.round(d * 25.4 / 96);//电脑端
} else {
return Math.round(d * 25.4 / 72);//手机端
}
}

            function pm2px(d) {                var iswindow = /windows|win32/i.test(navigator.userAgent);                if (iswindow) {                    return Math.round(d * 96 / 25.4);                } else {                    return Math.round(d * 72 / 25.4);                }            }