1. If the page has a canvas, it is necessary to inform the user to replace or update the browser. In this case replacement element may be performed by adding between <canvas> tag
< Canvas the above mentioned id = "c1" > Your browser does not support canvas, replace or update your browser </ Canvas >
<canvas id="c1"> <img src="/canvasError.jpg" /> </canvas>
2. If you provide a second set of program logic or behavior does not support the canvas browser, you need to determine whether the browser supports the canvas in js script.
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <canvas id="c1" width="300" height="300"></canvas> <script> determines whether the node has a canvas getContext method, if not, then the browser does not support the canvas//Draw (canvasElement) { function if (!canvasElement.getContext) return; var ctx = canvasElement.getContext("2d"); // code begin } var canvasElement = document.getElementById("c1"); draw(canvasElement); </script> </body> </html>