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Why isn't my JavaScript function able to access global-scope functions/variables defined in my other .js files?

开发者 https://www.devze.com 2022-12-15 21:00 出处:网络
I wrote a script like that: NS.load = function(src) { var script = document.createElement(\"script\").setAttribute(\"src\", src);

I wrote a script like that:

NS.load = function(src) {
    var script = document.createElement("script").setAttribute("src", src);
    document.getElementsByTagName("head")[0].appendChild(script);
}

It loads files but I can't reach functions and variables defiened in other files.

//js/main.js
var qux = {name: "name"};
NS.load("js/foo.js");

//js/foo.js
alert(qux.name); //undefined variable

But if I define qux like this:

window.qux = {name: "name"};

I can reach qux variable in other modules. As far as I know all globals 开发者_如何学JAVAare already a member of window object. So why I have to define variables like this. Could you offer another method?

Thanks.


It looks like you tried to shortcut your code by calling createElement and setAttribute all on 1 line, but setAttribute doesn't return anything, so you can't go calling appendChild on it's return value, because there is none.This will fix it:

NS.load = function(src) {
    var script = document.createElement("script");
    script.setAttribute("src", src)
    document.getElementsByTagName("head")[0].appendChild(script);
}

Edit:

What sort of environment are you running your code in? Is something happening cross-site or are you defining qux inside of another function? The following works for me, running the files via http://localhost/test.html

<html>
<head>
    <script type="text/javascript">
        load = function(src) {
            var script = document.createElement("script");
            script.setAttribute("src", src);
            document.getElementsByTagName("head")[0].appendChild(script);
        }
        var qux = {name: "name"};
        load("foo.js");
    </script>
</head>
<body></body>
</html>

foo.js:

alert(qux.name);

I get an alert with "name" when the page loads.

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