<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>图像缩放</title> <script src="js/modernizr.js"></script> </head> <body> <script type="text/javascript"> window.addEventListener('load',eventWindowLoaded,false); function eventWindowLoaded(){ canvasApp(); } function canvasSupport(){ return Modernizr.canvas; } function canvasApp(){ if(!canvasSupport()){ return; }else{ var theCanvas = document.getElementById('canvas') var context = theCanvas.getContext("2d") } drawScreen(); function drawScreen(){ context.setTransform(1,0,0,1,0,0); var x = 100; var y = 100; var width = 50; var height = 50; context.translate(x+.5*width,y+.5*height); context.scale(2,2);//横，纵 context.fillStyle="red"; context.fillRect(-.5*width,-.5*height,width,height); } } </script> <canvas id="canvas" width="500" height="500"> 你的浏览器无法使用canvas 小白童鞋；你的支持是我最大的快乐！！ </canvas> </body> </html>