從w3school上抄下來的

function checkVideo()
{
	if(!!document.createElement('video').canPlayType)
  	{
  		var vidTest=document.createElement("video");
  			oggTest=vidTest.canPlayType('video/ogg; codecs="theora, vorbis"');
  			if (!oggTest)
    		{
    			h264Test=vidTest.canPlayType('video/mp4; codecs="avc1.42E01E, mp4a.40.2"');
    			if (!h264Test)
      			{
      				document.getElementById("checkVideoResult").innerHTML="Sorry. No video support."
      			}
	    		else
	      		{
	      			if (h264Test=="probably")
	        		{
	        			document.getElementById("checkVideoResult").innerHTML="Yes! Full support!";
	        		}
	      			else
	        		{
	        			document.getElementById("checkVideoResult").innerHTML="Well. Some support.";
	        		}
	      		}
    		}
		    else
		    {
		    	if (oggTest=="probably")
		      	{
		      		document.getElementById("checkVideoResult").innerHTML="Yes! Full support!";
		      	}
		    	else
		      	{
		      		document.getElementById("checkVideoResult").innerHTML="Well. Some support.";
		      	}
		    }
  	}	
	else
  	{
  		document.getElementById("checkVideoResult").innerHTML="Sorry. No video support."
  	}
}