javascript不是java,它運行在瀏覽器中,java需要運行在JVM中,javascript屬於前端技術,java屬於後端技術
將javascript放到script標籤中
<html>
<head>
<script language="javascript">
alert("Hello World!!");
</script>
</head>
<body>
</body>
</html>
將javascript放到一個單獨的文件中
<html>
<head>
<script language="javascript" src="script/script.js"></script>
</head>
<body>
</body>
</html>
文件:script/script.js
alert("Hello World!!");
將javascript放到html元素中
<a href="javascript:alert('Hello World!!')">javascript</a>
在javascript的function中不用定義返回類型
<html>
<head>
<script language="javascript">
function sayHello() {
var p = "局部變量";
return p;
}
</script>
</head>
<!-- 在頁面載入的時候執行 -->
<body οnlοad="alert(sayHello())">
</body>
</html>
javascript中變量的轉換和eval
<script language="javascript">
var v1 = "10";
alert("v1=" + v1 + 1);
alert("parseInt(v1)=" + (parseInt(v1) + 1));
var v2 = "1.5";
alert("parseFloat(v2)=" + (parseFloat(v2) + 1));
var v3=11;
eval("var v" + v3 + "=" + v3); // var v11 = 11;
alert("v11=" + v11);
</script>