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waitForKeyElements gist port

A function that waits for a specific element to load before running a specified callback. portated from this GitHub gist: https://gist.github.com/BrockA/2625891#file-waitforkeyelements-js

此脚本不应直接安装，它是一个供其他脚本使用的外部库。如果您需要使用该库，请在脚本元属性加入：// @require https://update.cn-greasyfork.org/scripts/476008/1255570/waitForKeyElements%20gist%20port.js 

  1. // @require      http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js
  2.  
  3. /*--- waitForKeyElements():  A utility function, for Greasemonkey scripts,
  4.     that detects and handles AJAXed content.
  5.  
  6.     Usage example:
  7.  
  8.         waitForKeyElements (
  9.             "div.comments"
  10.             , commentCallbackFunction
  11.         );
  12.  
  13.         //--- Page-specific function to do what we want when the node is found.
  14.         function commentCallbackFunction (jNode) {
  15.             jNode.text ("This comment changed by waitForKeyElements().");
  16.         }
  17.  
  18.     IMPORTANT: This function requires your script to have loaded jQuery.
  19. */
  20. function waitForKeyElements (
  21.     selectorTxt,    /* Required: The jQuery selector string that
  22.                         specifies the desired element(s).
  23.                     */
  24.     actionFunction, /* Required: The code to run when elements are
  25.                         found. It is passed a jNode to the matched
  26.                         element.
  27.                     */
  28.     bWaitOnce,      /* Optional: If false, will continue to scan for
  29.                         new elements even after the first match is
  30.                         found.
  31.                     */
  32.     iframeSelector  /* Optional: If set, identifies the iframe to
  33.                         search.
  34.                     */
  35. ) {
  36.     var targetNodes, btargetsFound;
  37.  
  38.     if (typeof iframeSelector == "undefined")
  39.         targetNodes     = $(selectorTxt);
  40.     else
  41.         targetNodes     = $(iframeSelector).contents ()
  42.                                            .find (selectorTxt);
  43.  
  44.     if (targetNodes  &&  targetNodes.length > 0) {
  45.         btargetsFound   = true;
  46.         /*--- Found target node(s).  Go through each and act if they
  47.             are new.
  48.         */
  49.         targetNodes.each ( function () {
  50.             var jThis        = $(this);
  51.             var alreadyFound = jThis.data ('alreadyFound')  ||  false;
  52.  
  53.             if (!alreadyFound) {
  54.                 //--- Call the payload function.
  55.                 var cancelFound     = actionFunction (jThis);
  56.                 if (cancelFound)
  57.                     btargetsFound   = false;
  58.                 else
  59.                     jThis.data ('alreadyFound', true);
  60.             }
  61.         } );
  62.     }
  63.     else {
  64.         btargetsFound   = false;
  65.     }
  66.  
  67.     //--- Get the timer-control variable for this selector.
  68.     var controlObj      = waitForKeyElements.controlObj  ||  {};
  69.     var controlKey      = selectorTxt.replace (/[^\w]/g, "_");
  70.     var timeControl     = controlObj [controlKey];
  71.  
  72.     //--- Now set or clear the timer as appropriate.
  73.     if (btargetsFound  &&  bWaitOnce  &&  timeControl) {
  74.         //--- The only condition where we need to clear the timer.
  75.         clearInterval (timeControl);
  76.         delete controlObj [controlKey]
  77.     }
  78.     else {
  79.         //--- Set a timer, if needed.
  80.         if ( ! timeControl) {
  81.             timeControl = setInterval ( function () {
  82.                     waitForKeyElements (    selectorTxt,
  83.                                             actionFunction,
  84.                                             bWaitOnce,
  85.                                             iframeSelector
  86.                                         );
  87.                 },
  88.                 300
  89.             );
  90.             controlObj [controlKey] = timeControl;
  91.         }
  92.     }
  93.     waitForKeyElements.controlObj   = controlObj;
  94. }