Question

我正在开发一个脚本（扩展程序），它选择一个HTML标记并为它做一些事情。但是，此HTML标记会在某个给定时间在页面上动态加载，我想在加载后立即检测到它。目前我在while循环中查询html页面（检查未定义）但是它在页面上滞后很多。有解决方法吗？

$(document).ready(function() {
  // some code
  var sizesList=document.getElementsByClassName("exp-pdp-size-dropdown-container nsg-form--drop-down--option-container selectBox-options nsg-form--drop-down exp-pdp-size-dropdown exp-pdp-dropdown two-column-dropdown selectBox-dropdown-menu")[0];
  while(typeof(sizesList) == 'undefined') {
    setTimeout(function() {}, 700)
    sizesList=document.getElementsByClassName("exp-pdp-size-dropdown-container nsg-form--drop-down--option-container selectBox-options nsg-form--drop-down exp-pdp-size-dropdown exp-pdp-dropdown two-column-dropdown selectBox-dropdown-menu")[0];
  }
// some more code
}

我正在this网页上对其进行测试。

Answer 1

The page is lagging because you're executing sizesList=document.getElementsByClassName(... continuously. The setTimeout is asynchronous, so it won't do anything.

To poll every 700ms like you expect, you should consider setInterval:

setInterval(function() {
    if(typeof(sizesList) == 'undefined')
    sizesList=document.getElementsBy(...
}, 700)

Chrome扩展程序轮询html滞后页面

1 个答案: