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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/12228/175122/setMutationHandler.js 

  1. // ==UserScript==
  2. // @name          setMutationHandler
  3. // @description   MutationObserver wrapper to wait for the specified CSS selector
  4. // @namespace     wOxxOm.scripts
  5. // @author        wOxxOm
  6. // @grant         none
  7. // @version       3.0.2
  8. // ==/UserScript==
  9.  
  10. function setMutationHandler(target, selector, handler, options) {
  11. // or    setMutationHandler(selector, handler, options) {
  12. // or    setMutationHandler(options) {
  13. 	if (typeof arguments[0] == 'string') {
  14. 		options = arguments[2] || {};
  15. 		handler = arguments[1];
  16. 		selector = arguments[0];
  17. 		target = document;
  18. 	} else if (arguments.length == 1 && target && typeof target.handler == 'function') {
  19. 		options = arguments[0];
  20. 		handler = options.handler;
  21. 		selector = options.selector;
  22. 		target = options.target || document;
  23. 	} else if (!(target instanceof Node)) {
  24. 		throw 'Bad params for setMutationHandler.\n' +
  25. 			'A: [optional Node] target, [String] selector, [Function] handler, [optional Object] options\n' +
  26. 			'B: [Object] options\n' +
  27. 			'Options: target, selector, handler, processExisting, childList, attributes, characterData, subtree, attributeOldValue, characterDataOldValue, attributeFilter';
  28. 	} else
  29.     	options = options || {};
  30.  
  31. 	if (options.processExisting && target.querySelector(selector))
  32. 		handler.call(null, Array.prototype.slice.call(target.querySelectorAll(selector)));
  33. 	if (!options.attributes && !options.characterData && !options.childList && options.subtree === undefined)
  34. 		options.childList = options.subtree = true;
  35.  
  36. 	var cb;
  37. 	if (/^#[\w\d-]+$/.test(selector)) {
  38. 		selector = selector.substr(1);
  39. 		cb = MOhandlerForId;
  40. 	} else {
  41. 		cb = MOhandler;
  42. 	}
  43. 	var observer = new MutationObserver(cb);
  44. 	observer.observe(target, options || {subtree:true, childList:true});
  45. 	return observer;
  46.  
  47. 	function MOhandler(mutations) {
  48. 		if (mutations.length > 100 && !document.querySelector(selector))
  49. 			return;
  50. 		var found = [];
  51. 		for (var i=0, m; (m = mutations[i++]); ) {
  52. 			switch (m.type) {
  53. 				case 'childList':
  54. 					var nodes = m.addedNodes, nl = nodes.length;
  55. 					var textNodesOnly = true;
  56. 					for (var j=0; j < nl; j++) {
  57. 						var n = nodes[j];
  58. 						textNodesOnly &= n.nodeType == 3; // TEXT_NODE
  59. 						if (n.nodeType != 1) // ELEMENT_NODE
  60. 							continue;
  61. 						if (n.matches(selector))
  62. 							found.push(n);
  63. 						else if (n.querySelector(selector)) {
  64. 							n = n.querySelectorAll(selector);
  65. 							if (n.length < 1000)
  66. 								found.push.apply(found, n);
  67. 							else
  68. 								found = found.concat(found.slice.call(n));
  69. 						}
  70. 					}
  71. 					if (textNodesOnly && m.target.matches(selector))
  72. 						found.push(m.target);
  73. 					break;
  74. 				case 'attributes':
  75. 					if (m.target.matches(selector))
  76. 						found.push(m.target);
  77. 					break;
  78. 				case 'characterData':
  79. 					if (m.target.parentNode && m.target.parentNode.matches(selector))
  80. 						found.push(m.target.parentNode);
  81. 					break;
  82. 			}
  83. 		}
  84. 		if (!found.length)
  85. 			return;
  86. 		if (handler.call(observer, found) === false)
  87. 			observer.disconnect();
  88. 	}
  89.  
  90. 	function MOhandlerForId(mutations) {
  91. 		var el = document.getElementById(selector);
  92. 		if (el && target.contains(el))
  93. 			if (handler.call(observer, [el]) === false)
  94. 				observer.disconnect();
  95. 	}
  96. }