如何从我的 HTML/JavaScript 应用程序中引用 jQuery？
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How do I reference jQuery from my HTML/JavaScript application?
提问by Carlos Miguel Fernando
I keep getting Uncaught ReferenceError: $ is not definederror.
I assume everything is ok and working. My JQuery code is inside my Javascript file. I assume that isn't how it works? Should I have a JQuery file?
我不断收到Uncaught ReferenceError: $ is not defined错误。我假设一切正常并且工作正常。我的 JQuery 代码在我的 Javascript 文件中。我认为这不是它的工作原理？我应该有一个 JQuery 文件吗？
I have this inside the head of my HTML
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
我在我的 HTML 的头部里面有这个
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
This is my Javascript file:
这是我的 Javascript 文件：
function typing(id, sentence){
var result = $.Deferred();
var index=0;
var intObject= setInterval(function() {
document.getElementById(id).innerHTML+=sentence[index];
index++;
if(index==sentence.length){
clearInterval(intObject);
}
}, 100);
return result.promise();
}
var sleep = function(ms) {
var result = $.Deferred();
setTimeout(result.resolve, ms);
return result.promise();
};
typing('container','Subject Name:').then(function() {
return sleep(500);
}).then(function() {
return typing('container',' Carlos Miguel Fernando')
});
Where did I go wrong?
我哪里做错了？
回答by T.J. Crowder
Your question is fairly unclear, but essentially, you just have to make sure jQuery is loaded beforeyour code. So for instance:
您的问题相当不清楚，但本质上，您只需要确保在您的代码之前加载了 jQuery 。所以例如：
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<script src="your-code.js"></script>
or
或者
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<script>
// Your code
</script>
But not
但不是
<!-- Not like this -->
<script src="your-code.js"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
Note the order of tags.
注意标签的顺序。
These tags do not need to be in the head, and in fact, putting them there is not best practice. They must be in heador body. Best practice barring a specific reason to do something else is to put them at the very end of body, e.g.:
这些标签不需要在 中head，事实上，把它们放在那里并不是最佳实践。它们必须在head或 中body。除非有特定原因做其他事情的最佳实践是将它们放在 的最后body，例如：
<!-- site content here -->
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<script src="your-code.js"></script>
</body>
</html>
