☰

Wait For Elements

given a selector waits for elements to be inserted into the DOM and executes a callback for each match

当前为 2016-05-01 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/5679/122960/Wait%20For%20Elements.js 

  1. /**
  2. * @param sel - the selector you want to wait for
  3. * @param action - the callback that will be executed when element/s matching the given selector are found, it is passed the array of found elements
  4. * @param stopLooking - if true the function will stop looking for more elements after the first match
  5. */
  6. function waitForElems(sel, action, stopLooking) {
  7.   var tick;
  8.   var id = 'fke' + Math.floor(Math.random() * 12345);
  9.   var type = window.MutationObserver ? 'M' : 'S';
  10.   var lastCall = Date.now();
  11.   var queuedCall;
  12.   function throttle(func) {
  13.     var now = Date.now();
  14.     clearTimeout(queuedCall);
  15.     if(now - lastCall < 100) {
  16.       queuedCall = setTimeout(func, 100);
  17.     } else {
  18.       func();
  19.     }
  20.     lastCall = now;
  21.   }
  22.   function findElem(sel) {
  23.     var found = [].filter.call(document.querySelectorAll(sel), function(elem) {
  24.       return elem.dataset[id] !== 'y';
  25.     });
  26.     if(found.length > 0) {
  27.       if(stopLooking) {
  28.         type === 'M' ? tick.disconnect() : clearInterval(tick);
  29.       }
  30.       found.forEach(function(elem) {
  31.         elem.dataset[id] = 'y';
  32.         action(elem);
  33.       });
  34.     }
  35.   }
  36.   if(type === 'M') {
  37.     tick = new MutationObserver(throttle.bind(null, findElem.bind(null, sel)));
  38.     tick.observe(document.body, { subtree: true, childList: true });
  39.   } else {
  40.     tick = setInterval(findElem.bind(null, sel), 300);
  41.   }
  42.   findElem(sel);
  43.   return tick;
  44. }
  45. /**
  46. * @param regex - should match the site you're waiting for
  47. * @param action - the callback that will be executed when a matching url is visited
  48. * @param stopLooking - if true the function will stop waiting for another url match after the first match
  49. */
  50. function waitForUrl(regex, action, stopLooking) {
  51.   function checkUrl(urlTest) {
  52.     var url = window.location.href;
  53.     if(url !== lastUrl && urlTest(url)) {
  54.       if(stopLooking) {
  55.         clearInterval(tick);
  56.       }
  57.       lastUrl = url;
  58.       action();
  59.     }
  60.     lastUrl = url;
  61.   }
  62.   var urlTest = (typeof regex === 'function' ? regex : regex.test.bind(regex)),
  63.       tick = setInterval(checkUrl.bind(null, urlTest), 300),
  64.       lastUrl;
  65.   checkUrl(urlTest);
  66.   return tick;
  67. }