检测HTML5< canvas>的最佳方式不支持 [英] Best way to detect that HTML5 <canvas> is not supported

问题描述

处理浏览器不支持HTML5 < canvas> 标记的情况的标准方法是嵌入一些后备内容，如：

 < canvas>您的浏览器不支持canvas。< / canvas> 
  

但页面的其余部分保持不变，这可能不恰当或具有误导性。我想要一些方法来检测画布不支持，以便我可以相应地呈现我的页面的其余部分。

解决方案

这是Modernizr中使用的技术，基本上是每个其他的画布工作的库：

  function isCanvasSupported（）{
 var elem = document.createElement（'canvas'）; 
 return !!（elem.getContext& elem.getContext（'2d'））; 
} 
  

由于您的问题是不是支持，我建议使用它像这样：

  if（！isCanvasSupported（））{... 
  




The standard way to deal with situations where the browser does not support the HTML5 <canvas> tag is to embed some fallback content like:

<canvas>Your browser doesn't support "canvas".</canvas>

But the rest of the page remains the same, which may be inappropriate or misleading. I'd like some way of detecting canvas non-support so that I can present the rest of my page accordingly. What would you recommend?

解决方案

This is the technique used in Modernizr and basically every other library that does canvas work:

function isCanvasSupported(){
  var elem = document.createElement('canvas');
  return !!(elem.getContext && elem.getContext('2d'));
}

Since your question was for detection when it's not supported, I recommend using it like so:

if (!isCanvasSupported()){ ...

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