使用一個回調函數在Javascript

打開http://jaminweb.com/YoutubePlaylist.html
輸入sMqNFAU0tOw（或任何其他YouTube視頻ID）到播放列表
點擊播放影片！
JavaScript控制檯應該說，像未捕獲TypeError: undefined is not a function

在嘗試診斷問題：

的播放影片！按鈕調用下面的函數

 this.playAll = function() 
     { 
      var vidtexts = document.getElementsByClassName('vidtxt'); 
      for (var i = 0, j = vidtexts.length; i < j; ++i) 
      { 
       var thisid = vidtexts[i].value; 
       if (thisid.length > 0) 
       { 
        var thisurl = "http://www.youtube.com/v/" + thisid + "?enablejsapi=1&playerapiid=ytplayer&version=3";      
        var atts = { id: "myytplayer" }; 
        var params = { allowScriptAccess: "always" }; 

        swfobject.embedSWF(thisurl, "playerdiv", "425", "356", "8", null, null, params, atts, this.playVid); 

       } 
      } 
     }

依次調用下面的函數

 this.playVid = function(e) 
     { 
      /* Callback function for swfobject.embedSWF(...), to play the video 
       if the flash player was loaded successfully. */ 
      if (e.success) 
      { 
       var ytplayer = document.getElementById("myytplayer"); 
       ytplayer.playVideo(); 
       while (ytplayer.getPlayerState() == 1) {;} // need to change this sometime lol 
      } 
     }

控制檯錯誤指向行

ytplayer.playVideo();

所以問題是對象ytplayer在調用playVideo()時尚未實例化。我不明白這是爲什麼，因爲當我用我包括作爲可選參數的函數

    swfobject.embedSWF(thisurl, "playerdiv", "425", "356", "8", null, null, params, atts, this.playVid);

回調函數this.playVid我寫信給調用只有當與ID myytplayer一個swf對象被創建ytplayer.playVideo();。

來源

2014-06-10 Holy Diver

這個工程鉻。並在IE 10中。

VideoPlayer = function() { 
     this.addVideo = function() { 
      var newVidElement = document.createElement("div"); 
      newVidElement.className = "videl"; 
      newVidElement.innerHTML = "<p><textarea class='vidtxt'></textarea><img class='rembtn' src='remicon.png' width=20 height=20></img></p>"; 
      document.getElementById("vidplaydiv").appendChild(newVidElement); 
     } 
     this.playAll = function() { 
      var vidtexts = document.getElementsByClassName('vidtxt'); 
      for (var i = 0, j = vidtexts.length; i < j; ++i) { 
       var thisid = vidtexts[i].value; 
       if (thisid.length > 0) { 
        var thisurl = "http://www.youtube.com/v/" + thisid + "?enablejsapi=1&playerapiid=ytplayer&version=3"; 
        var atts = { 
         id: "myytplayer" 
        }; 
        var params = { 
         allowScriptAccess: "always" 
        }; 

        swfobject.embedSWF(thisurl, "playerdiv", "425", "356", "8", null, null, params, atts, this.playVid); 

       } 
      } 
     } 
     this.playVid = function (e) { 
      /* Callback function for swfobject.embedSWF(...), to play the video 
       if the flash player was loaded successfully. */ 
      if (e.success) { 
       var ytplayer = document.getElementById("myytplayer"); 
       ytplayer.playVideo(); 
       while (ytplayer.getPlayerState() == 1) {; 
       } // need to change this 
      } 
     } 
    }

來源

2014-06-11 01:12:35

使用一個回調函數在Javascript

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