blocks|key|1237198|text|在包含helpers.js文件之前，需要先声明变量。只需在helpers.js的include上创建一个脚本标记，并在那里定义它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1237199|<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>|code-block|syntax|javascript|1237200|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>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.</p>

<pre><code>&lt;script type='text/javascript' &gt; 
  var myFunctionTag = false; 
&lt;/script&gt;
&lt;script type='text/javascript' src='js/helpers.js'&gt;&lt;/script&gt;     
... 
&lt;script type='text/javascript' &gt; 
  // rest of your code, which may depend on helpers.js
&lt;/script&gt;
</code></pre>


blocks|key|1022601|text|该变量可以在.js文件中声明，也可以在HTML文件中引用。我的helpers.js版本|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1022602|var+myFunctionWasCalled+=+false;

function+doFoo()
{
++++if+(!myFunctionWasCalled)+{
++++++++alert("doFoo+called+for+the+very+first+time!");
++++++++myFunctionWasCalled+=+true;
++++}
++++else+{
++++++++alert("doFoo+called+again");
++++}
}|code-block|syntax|javascript|1022603|和一个页面来测试它：|1022604|<html>
<head>
<title>Test+Page</title>
<meta+http-equiv="Content-Type"+content="text/html;+charset=UTF-8"/>
<script+type="text/javascript"+src="helpers.js"></script>
</head>

<body>


<p>myFunctionWasCalled+is
<script+type="text/javascript">document.write(myFunctionWasCalled);</script>
</p>

<script+type="text/javascript">doFoo();</script>

<p>Some+stuff+in+between</p>

<script+type="text/javascript">doFoo();</script>

<p>myFunctionWasCalled+is
<script+type="text/javascript">document.write(myFunctionWasCalled);</script>
</p>

</body>
</html>|1022605|您将看到测试alert()将显示两个不同的内容，并且第二次写入页面的值将不同。|1022606|entityMap^0|6|3|V|A|0|0|0|0|6|7|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

<p>The variable can be declared in the <code>.js</code> file and simply referenced in the HTML file.
My version of <code>helpers.js</code>:</p>

<pre><code>var myFunctionWasCalled = false;

function doFoo()
{
    if (!myFunctionWasCalled) {
        alert("doFoo called for the very first time!");
        myFunctionWasCalled = true;
    }
    else {
        alert("doFoo called again");
    }
}
</code></pre>

<p>And a page to test it:</p>

<pre><code>&lt;html&gt;
&lt;head&gt;
&lt;title&gt;Test Page&lt;/title&gt;
&lt;meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/&gt;
&lt;script type="text/javascript" src="helpers.js"&gt;&lt;/script&gt;
&lt;/head&gt;

&lt;body&gt;


&lt;p&gt;myFunctionWasCalled is
&lt;script type="text/javascript"&gt;document.write(myFunctionWasCalled);&lt;/script&gt;
&lt;/p&gt;

&lt;script type="text/javascript"&gt;doFoo();&lt;/script&gt;

&lt;p&gt;Some stuff in between&lt;/p&gt;

&lt;script type="text/javascript"&gt;doFoo();&lt;/script&gt;

&lt;p&gt;myFunctionWasCalled is
&lt;script type="text/javascript"&gt;document.write(myFunctionWasCalled);&lt;/script&gt;
&lt;/p&gt;

&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>You'll see the test <code>alert()</code> will display two different things, and the value written to the page will be different the second time.</p>


blocks|key|1237357|text|我认为你应该使用“局部存储”而不是全局变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1237358|如果您担心“本地存储”在非常旧的浏览器中可能不受支持，请考虑使用现有的插件来检查“本地存储”的可用性，如果它不可用，则使用其他方法。|1237359|我使用了http://www.jstorage.info/，到目前为止我对它很满意。|offset|length|1237360|entityMap|0|LINK|mutability|MUTABLE|url|http://www.jstorage.info/^0|0|0|4|P|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

<p>I think you should be using "local storage" rather than global variables.</p>

<p>If you are concerned that "local storage" may not be supported in very old browsers, consider using an existing plug-in which checks the availability of "local storage" and uses other methods if it isn't available.</p>

<p>I used  <a href="http://www.jstorage.info/" rel="nofollow">http://www.jstorage.info/</a> and I'm happy with it so far.</p>


blocks|key|1237385|text|您可以创建如下json对象：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1237386|globalVariable={example_attribute:"SomeValue"};+|code-block|syntax|javascript|1237387|在fileA.js中|1237388|并像这样从fileB.js访问它：globalVariable.example_attribute|offset|length|style|CODE|1237389|entityMap^0|0|0|0|H|W|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

<p>You can make a json object like:</p>

<pre><code>globalVariable={example_attribute:"SomeValue"}; 
</code></pre>

<p>in fileA.js </p>

<p>And access it from fileB.js like: 
<code>globalVariable.example_attribute</code></p>


blocks|key|1237418|text|您好，要将值从一个js文件传递到另一个js文件，我们可以使用本地存储概念|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1237419|<body>
<script+src="two.js"></script>
<script+src="three.js"></script>
<button+onclick="myFunction()">Click+me</button>
<p+id="demo"></p>
</body>|code-block|syntax|javascript|1237420|Two.js文件|1237421|function+myFunction()+{
var+test+=localStorage.name;

+alert(test);
}|1237422|Three.js文件|1237423|localStorage.name+=+1;|1237424|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

<p>Hi to pass values from one js file to another js file we can use Local storage concept</p>

<pre><code>&lt;body&gt;
&lt;script src="two.js"&gt;&lt;/script&gt;
&lt;script src="three.js"&gt;&lt;/script&gt;
&lt;button onclick="myFunction()"&gt;Click me&lt;/button&gt;
&lt;p id="demo"&gt;&lt;/p&gt;
&lt;/body&gt;
</code></pre>

<p>Two.js file</p>

<pre><code>function myFunction() {
var test =localStorage.name;

 alert(test);
}
</code></pre>

<p>Three.js File</p>

<pre><code>localStorage.name = 1;
</code></pre>


<p>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.</p>

<p>I have attempted to create a global variable by defining:</p>

<pre><code>var myFunctionTag = true;
</code></pre>

<p>In global scope both in my HTML code and in helpers.js.</p>

<p>Heres what my html code looks like:</p>

<pre><code>&lt;html&gt;
...
&lt;script type='text/javascript' src='js/helpers.js'&gt;&lt;/script&gt;    
...
&lt;script&gt;
  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
&lt;/script&gt;
</code></pre>

<p>Is what I am trying to do even feasible? </p>


Global variables in Javascript across multiple files

我的一堆JavaScript代码在一个名为helpers.js的外部文件中。在调用这段JavaScript代码的超文本标记语言中，我发现自己需要知道是否调用了来自helpers.js的某个函数。我尝试通过定义以下内容来创建全局变量：var myFunctionTag = true;在我的HTML代码和helpers.j...

问Javascript中跨多个文件的全局变量
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Javascript中跨多个文件的全局变量EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Javascript中跨多个文件的全局变量
EN