JavaScript: Where to Insert JavaScript and output

1、Javescript in <head>

<!DOCTYPE html>
<html>
<head>
<script>
function myFunction() {
  document.getElementById("demo").innerHTML = "Paragraph changed.";
}
</script>
</head>
<body>

<h2>JavaScript in Head</h2>

<p id="demo">A Paragraph.</p>

<button type="button" onclick="myFunction()">Try it</button>

</body>
</html>

2、Javescript in <body>

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript in Body</h2>

<p id="demo">A Paragraph.</p>

<button type="button" onclick="myFunction()">Try it</button>

<script>
function myFunction() {
  document.getElementById("demo").innerHTML = "Paragraph changed.";
}
</script>

</body>
</html>

3、Javescript in an external file、url、 folder

<!DOCTYPE html>
<html>
<body>

<h2>External JavaScript</h2>

<p id="demo">A Paragraph.</p>

<button type="button" onclick="myFunction()">Try it</button>

<p>(myFunction is stored in an external file called "myScript.js")</p>

<script src="myScript.js"></script>
<script src="https://www.w3schools.com/js/myScript.js"></script>
<script src="/js/myScript.js"></script>

</body>
</html>

writing into the html output / html elemnt / window alert box/ browser console

posted @ 2019-03-27 17:52  Nyan  阅读(165)  评论(0)  编辑  收藏  举报