html5学习之路（Canvas画布1）
使用canvas画一个矩形，圆和直线
<!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>canvas示例</title><script type="text/javascript">function mydrawRect(){var canvas=document.getElementById("rect");if (canvas==null){return false;}var context=canvas.getContext('2d');context.fillStyle="#EEEEFF";context.fillRect(0,0,400,300);context.fillStyle="red";context.strokeStyle="blue";context.lineWidth=1;//绘制一个矩形context.fillRect(50,50,100,100);context.strokeRect(50,50,100,100);//绘制一个圆context.beginPath();context.arc(200,200,50,0,Math.PI*2,true);context.closePath();context.fillStyle='rgba(255,0,0,0.25)';context.fill();//画直线context.beginPath();context.moveTo(100,100);context.lineTo(100,300);context.lineTo(300,300);context.closePath();//context.fillStyle='rgba(255,0,0,0.25)';//context.fill();context.stroke();}</script></head><body onload="return mydrawRect();"><canvas id="rect" width="400" height="300"></body></html>显示效果：