网页添加水印

调用即可

 1 function addWaterMarker(str){
 2 
 3 
 4     var can = document.createElement('canvas');
 5     var body = document.body;
 6 
 7     body.appendChild(can);
 8 
 9     can.width=400;
10     can.height=200;
11     can.style.display='none';
12 
13 
14     var cans = can.getContext('2d');
15     cans.rotate(-20*Math.PI/180);
16     cans.font = "16px Microsoft JhengHei";
17     cans.fillStyle = "rgba(17, 17, 17, 0.50)";
18     cans.textAlign = 'left';
19     cans.textBaseline = 'Middle';
20     cans.fillText(str,can.width/3,can.height/2);
21 
22     body.style.backgroundImage="url("+can.toDataURL("image/png")+")";
23 
24 }