问题描述
所以我最近从 ThemeForest 购买并下载了一个模板.我在本地服务器上设置了模板.我使用 codeigniter 生成了具有下拉菜单的导航.我将菜单中的所有内容都正确编码.我只生成了标题并进行了测试，并意识到下拉菜单不起作用.我花了大约两个小时试图找出我的代码出了什么问题.然后我终于意识到 JavaScript 文件包含在模板的页脚中......我还没有生成.
So I recently bought and downloaded a template from ThemeForest. I set up the template on my local server. I generated the navigation, which has dropdown menus, with codeigniter. I had everything in the menu coded correctly. I only had the header generated and went to test it out and realized the dropdown menus were not working. I spent about two hours trying to figure out what was wrong with my code. Then I finally realized that the JavaScript files were included in the footer of the template... which I had not yet generated.
所以我的问题是……为什么有人会将 JavaScript 文件放在 HTML 页面的页脚中?我认为 JS 只应该位于文件的标题中.对吧?
So my question is... why would someone put JavaScript files in the footer of an HTML page? I thought that JS was only supposed to be located in the header of the file. Right?
推荐答案
您可以通过多种方式将脚本文件加载到网页.
There are different ways you could load a script file to a web page.
但是在页面底部加载脚本有以下优点.
But loading scripts at bottom of you page have the following advantages.
- 不会阻止任何要加载的 DOM 内容.
- 所有 DOM 元素都可用于正在加载的脚本.
- 如果您使用第三方库，例如 jQuery，则可以跳过
$(document).ready(function () {...});，因为 DOM 已经加载.
- Will not block any DOM content to be loaded.
- All the DOM elements will be available for the scripts that are being loaded.
- If you are using third-party libraries such as jQuery, you can skip the
$(document).ready(function () {...});as the DOM is already loaded.
希望这会有所帮助.
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