Javascript中的全局变量跨多个文件 [英] Global variables in Javascript across multiple files
问题描述
我的一些JavaScript代码位于名为helpers.js的外部文件中。在调用此JavaScript代码的HTML内部，我发现自己需要知道helpers.js中的某个函数是否已被调用。
A bunch of my JavaScript code is in an external file called helpers.js. Inside the HTML that calls this JavaScript code I find myself in need of knowing if a certain function from helpers.js has been called.
我试图创建一个全局变量通过定义：
I have attempted to create a global variable by defining:
var myFunctionTag = true;
全局范围都在我的HTML代码和helpers.js中。
In global scope both in my HTML code and in helpers.js.
继承我的html代码的样子：
Heres what my html code looks like:
<html>
...
<script type='text/javascript' src='js/helpers.js'></script>
...
<script>
var myFunctionTag = false;
...
//I try to use myFunctionTag here but it is always false, even though it has been se t to 'true' in helpers.js
</script>
我试图做甚至可行吗？
Is what I am trying to do even feasible?
推荐答案
您需要在包含helpers.js文件之前声明该变量。只需在include for helpers.js上面创建一个脚本标记并在其中定义即可。
You need to declare the variable before you include the helpers.js file. Simply create a script tag above the include for helpers.js and define it there.
<script type='text/javascript' >
var myFunctionTag = false;
</script>
<script type='text/javascript' src='js/helpers.js'></script>
...
<script type='text/javascript' >
// rest of your code, which may depend on helpers.js
</script>
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