Vue is not defined

user_1231505 0
Viewed 182023

I am trying to build a demo app with Vue.js. What I am getting is an odd error that Vue is not defined.

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Vue JS Intro</title>
</head>
<body>
    <div id="demo">
        <p>{{message}}</p>
        <input v-model="message">
    </div>

    <script type="JavaScript" src="https://cdnjs.cloudflare.com/ajax/libs/vue/1.0.18/vue.min.js"></script>

    <script>
        var demo = new Vue({
            el: '#demo',
            data: {
                message: 'Hello Vue.js!'
            }
        })
    </script>
</body>
</html>

What did I miss here? This is not a CDN issue as I also downloaded the library from the official website, used it and got the same result

index.html:15 Uncaught ReferenceError: Vue is not defined

vue.js html javascript
9 Answers

I got this error but as undefined due to the way I included js files

Initailly i had 

<script src="~/vue/blade-account-update-credit-card-vue.js" asp-append-version="true"></script>
<script src="~/lib/vue/vue_v2.5.16.js"></script>

in the end of my .cshtml page GOT Error Vue not Defined but later I changed it to

<script src="~/lib/vue/vue_v2.5.16.js"></script> 
<script src="~/vue/blade-account-update-credit-card-vue.js" asp-append-version="true"></script>

and magically it worked. So i assume that vue js needs to be loaded on top of the .vue

user_22988460

I found two main problems with that implementation. First, when you import the vue.js script you use type="JavaScript" as content-type which is wrong. You should remove this type parameter because by default script tags have text/javascript as default content-type. Or, just replace the type parameter with the correct content-type which is type="text/javascript".

The second problem is that your script is embedded in the same HTML file means that it may be triggered first and probably the vue.js file was not loaded yet. You can fix this using a jQuery snippet $(function(){ /* ... */ }); or adding a javascript function as shown in this example: 

// Verifies if the document is ready
function ready(f) {
  /in/.test(document.readyState) ? setTimeout('ready(' + f + ')', 9) : f();
}

ready(function() {
  var demo = new Vue({
    el: '#demo',
    data: {
      message: 'Hello Vue.js!'
    }
  })
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="demo">
  <p>{{message}}</p>
  <input v-model="message">
</div>

user_53720080

I had the same problem and for a strange reason, the js that contains the Vue, has a defer inside the script definition:

<script src="js/app.js" defer></script>

That caused the script loads asynchronously than the other js files.

After I remove the defer tag, the problem was solved.

user_37011020

For those who are facing this error in src/main.js file in vue,

just add :-

var Vue = require('vue')

Then, It will work fine.

user_173920160

just put text/javascript in your script tag which you use for cdn

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js" type="text/javascript"></script>
user_111463990
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