Canvas in the HTML5

The width of the 1.Canvas label must be set on the label or with JS to add attributes, if you use CSS to set the canvas will be stretched, equivalent to the default canvas stretched to the specified position. The default is 300px*100px;

<widthheight=400></canvas> 

Or

Canvas=document.getelementsbytagname (' canvas ') [0];canvas.width=500; canvas.height= 400;

This will solve the problem in the canvas.

2, the canvas drawing step order to step, or it will be covered according to the steps, attention!

3, a pixel in the canvas ask the question, because the canvas is filled from the middle to the sides of the drawing, but because the browser parsing, integer parsing (rounding) so there will be a pixel into two pixels of the problem, the solution, draw point offset 0.5;

Ctx.strokerect (10.5,10.5,100,100);

Canvas in the HTML5