js Timer has the following two methods:
- setInterval(): Calls a function or evaluates an expression at specified intervals (in milliseconds). The method will keep calling the function until clearInterval() is called or the window is closed.
- setTimeout(): Calls a function or evaluates an expression after a specified number of milliseconds.
setInterval()
Syntax
setInterval(code,millisec,lang)
| Parameter | Description |
|---|---|
| code | Required. The function to be called or the code string to be executed. |
| millisec | Required. The time interval (in milliseconds) between each periodic execution or call of code. |
| lang | Optional. JScript | VBScript | JavaScript |
The following example executes the clock() function every 1000 milliseconds. The example also includes a button to stop the execution:
<html>
<body>
<input type="text" id="clock" />
<script type="text/javascript">
var int=self.setInterval("clock()",1000);
function clock()
{
var d=new Date();
var t=d.toLocaleTimeString();
document.getElementById("clock").value=t;
}
</script>
<button onclick="int=window.clearInterval(int)">停止</button>
</body>
</html>
setTimeout()
Syntax
setTimeout(code,millisec,lang)
| Parameter | Description |
|---|---|
| code | Required. The JavaScript code string to be called or executed. |
| millisec | Required. The number of milliseconds to wait before executing the code. |
| lang | Optional. The scripting language can be: JScript | VBScript | JavaScript |
The following example demonstrates:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Example(example.com)</title>
</head>
<body>
<p>点击按钮，在等待 3 秒后弹出 "Hello"。</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction()
{
setTimeout(function(){alert("Hello")},3000);
}
</script>
</body>
</html>