基于js判断浏览器是否支持webGL

function getChromeVersion() {
    var arr = navigator.userAgent.split(' '); 
    var chromeVersion = '';
    for(var i=0;i < arr.length;i++){
      if(/chrome/i.test(arr[i]))
      chromeVersion = arr[i]
    }
    if(chromeVersion){
      return Number(chromeVersion.split('/')[1].split('.')[0]);
    } else {
      return false;
    }
  }

var Detector = {
  canvas: !!window.CanvasRenderingContext2D,
  webgl: (function() {
    try {
      var canvas = document.createElement('canvas');
      return !!(window.WebGLRenderingContext && (canvas.getContext('webgl') || canvas.getContext('experimental-webgl')));
    } catch(e) {
      return false;
    }
  })(),
  workers: !!window.Worker,
  fileapi: window.File && window.FileReader && window.FileList && window.Blob,
  getWebGLErrorMessage: function() {
    var element = document.createElement('div');
    element.id = 'webgl-error-message';
    element.style.fontFamily = 'monospace';
    element.style.fontSize = '13px';
    element.style.fontWeight = 'normal';
    element.style.textAlign = 'center';
    element.style.background = '#fff';
    element.style.color = '#000';
    element.style.padding = '1.5em';
    element.style.width = '400px';
    element.style.margin = '5em auto 0';
    if(!this.webgl) {
      element.innerHTML = window.WebGLRenderingContext ? [
        'Your graphics card does not seem to support <a href="http://khronos.org/webgl/wiki/Getting_a_WebGL_Implementation" rel="external nofollow" rel="external nofollow"  style="color:#000">WebGL</a>.<br />',
        'Find out how to get it <a href="http://get.webgl.org/" rel="external nofollow" rel="external nofollow"  style="color:#000">here</a>.'
      ].join('\n') : [
        'Your browser does not seem to support <a href="http://khronos.org/webgl/wiki/Getting_a_WebGL_Implementation" rel="external nofollow" rel="external nofollow"  style="color:#000">WebGL</a>.<br/>',
        'Find out how to get it <a href="http://get.webgl.org/" rel="external nofollow" rel="external nofollow"  style="color:#000">here</a>.'
      ].join('\n');
    }
    return element;
  },
  addGetWebGLMessage: function(parameters) {
    var parent, id, element;
    parameters = parameters || {};
    parent = parameters.parent !== undefined ? parameters.parent : document.body;
    id = parameters.id !== undefined ? parameters.id : 'oldie';
    element = Detector.getWebGLErrorMessage();
    element.id = id;
    parent.appendChild(element);
  }
};
if(typeof module === 'object') {
  module.exports = Detector;
}