選擇圖像或視頻

Question

我想弄清楚如何在html中顯示圖像或視頻。爲了澄清，我想顯示視頻，但如果視頻不存在或文件未找到，我想要顯示默認圖片。基本上是一個圖像文件顯示，如果視頻不會或不存在。這甚至有可能嗎？我一直試圖弄清楚這一點。沒有運氣。任何幫助，將不勝感激。

Answer 1

檢出這段代碼，它提供HTML5視頻後備到Flash和Flash後備到簡單圖像，而不會涉及任何JavaScript！

<!-- first try HTML5 playback: if serving as XML, expand `controls` to `controls="controls"` and autoplay likewise --> 
<!-- warning: playback does not work on iOS3 if you include the poster attribute! fixed in iOS4.0 --> 
<video width="100%" height="200px" controls> 

    <!-- MP4 must be first for iPad! --> 
    <source src="__VIDEO__.MP4" type="video/mp4" /><!-- Safari/iOS video --> 
    <source src="__VIDEO__.OGV" type="video/ogg" /><!-- Firefox/Opera/Chrome10 --> 

    <!-- fallback to Flash: --> 
    <object width="640" height="360" type="application/x-shockwave-flash" data="__FLASH__.SWF"> 

     <!-- Firefox uses the `data` attribute above, IE/Safari uses the param below --> 
     <param name="movie" value="__FLASH__.SWF" /> 
     <param name="flashvars" value="controlbar=over&amp;image=__POSTER__.JPG&amp;file=__VIDEO__.MP4" /> 

     <!-- fallback image. note the title field below, put the title of the video there --> 
     <img src="__VIDEO__.JPG" width="640" height="360" alt="__TITLE__" 
     title="No video playback capabilities, please download the video below" /> 
    </object> 
</video> 

<!-- you *must* offer a download link as they may be able to play the file locally. customise this bit all you want --> 
<p>  
    <strong>Download Video:</strong> 
    Closed Format: <a href="__VIDEO__.MP4">"MP4"</a> 
    Open Format: <a href="__VIDEO__.OGV">"Ogg"</a> 
</p>​