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setMutationHandler

MutationObserver wrapper to wait for the specified CSS selector

当前为 2016-10-10 提交的版本，查看 最新版本。

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/12228/151756/setMutationHandler.js 

  1. /* EXAMPLE:
  2. 	
  3. 	setMutationHandler(document, '.container p.some-child', function(nodes) {
  4. 		// single node:
  5. 		nodes[0].remove();
  6. 		
  7. 		// or multiple nodes:
  8. 		nodes.forEach(function(node) {
  9. 			node.style.display = 'none';
  10. 		});
  11.  
  12. 		//this.disconnect(); // disconnect the observer, this is useful for one-time jobs
  13. 	});
  14. */
  15.  
  16. // ==UserScript==
  17. // @name          setMutationHandler
  18. // @description   MutationObserver wrapper to wait for the specified CSS selector
  19. // @namespace     wOxxOm.scripts
  20. // @author        wOxxOm
  21. // @grant         none
  22. // @version       2.0.9
  23. // ==/UserScript==
  24.  
  25. function setMutationHandler(baseNode, selector, cb, options) {
  26. 	var ob = new MutationObserver(function MOhandler(mutations) {
  27. 		if (mutations.length > 100 && !document.querySelector(selector))
  28. 			return;
  29. 		var found = [];
  30. 		for (var i=0, ml=mutations.length; i < ml; i++) {
  31. 			var m = mutations[i];
  32. 			switch (m.type) {
  33. 				case 'childList':
  34. 					var nodes = m.addedNodes, nl = nodes.length;
  35. 					var textNodesOnly = true;
  36. 					for (var j=0; j < nl; j++) {
  37. 						var n = nodes[j];
  38. 						textNodesOnly &= n.nodeType == 3; // TEXT_NODE
  39. 						if (n.nodeType != 1) // ELEMENT_NODE
  40. 							continue;
  41. 						if (n.matches(selector))
  42. 							found.push(n);
  43. 						else if (n.querySelector(selector)) {
  44. 							n = n.querySelectorAll(selector);
  45. 							if (n.length < 1000)
  46. 								found.push.apply(found, n);
  47. 							else
  48. 								found = found.concat(found.slice.call(n));
  49. 						}
  50. 					}
  51. 					if (textNodesOnly && m.target.matches(selector))
  52. 						found.push(m.target);
  53. 					break;
  54. 				case 'attributes':
  55. 					if (m.target.matches(selector))
  56. 						found.push(m.target);
  57. 					break;
  58. 				case 'characterData':
  59. 					if (m.target.parentNode && m.target.parentNode.matches(selector))
  60. 						found.push(m.target.parentNode);
  61. 					break;
  62. 			}
  63. 		}
  64. 		if (found.length)
  65. 			cb.call(ob, found);
  66. 	});
  67. 	ob.observe(baseNode, options || {subtree:true, childList:true});
  68. 	return ob;
  69. }