广告自动显示和自动关闭
<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8">
<title></title>
<script>
function hideAD(){
var img = document.getElementById("img1");
img.style.display = "none";
}
function showAD(){
var img = document.getElementById("img1");
img.style.display = "block";
setTimeout("hideAD()",3000);
}
function init(){
setTimeout("showAD()",3000);
}
</script>
</head>
<body onload = "init()">
<img id = "img1" src = "../img/广告.jpg" width = "100%" style = "display:none" />
</body>
</html>
填写东西时候的提示(onfocus获得焦点)和(onblur失去焦点)
<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8">
<title></title>
<script>
function showTips(){
var span = document.getElementById("span_username");
span.innerHTML = "用户名长度不能小于6位";
}
function checkUsername(){
var uValue = document.getElementById("username").value;
var span = document.getElementById("span_username");
if(uValue.length < 6){
span.innerHTML = "<font color='red' size='2'>对不起，太短</font>";
}else{
span.innerHTML = "<font color='red' size='2'>恭喜你，可用</font>";
}
</script>
</head>
<body>
<form action = "../首页.html">
用户名：<input type="text" id="username" onfocus="showTips()" onblur="checkUsername()"/><span id="span_username"></span><br />
密码：<input type = "password" id = "password" /><br />
<form>
</body>
</html>