<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS响应事件练习</title>
<meta charset="utf-8" />
</head>
<body>
用户名： <input type="text" />
<br />
<br />
<input type="button" value="确定" id="click" />
<script>
document.write("<br/>");
btn = document.getElementById("click");
btn.onclick = function () {
alert("HelloWorld!")
}
</script>
<img src="a.jpg" id="a" />
<script>
document.getElementById("a").onmouseover = function () {
this.src = "b.jpg";
}
document.getElementById("a").onmouseout = function () {
this.src = "a.jpg";
}
</script>
<form id="form1" action="http://www.baidu.com">
用户名：<input type="text" id="name" />
<br />
<br />
<input type="submit" />
<script>
document.getElementById("form1").onsubmit = function () {
name = document.getElementById("name").value;
if (name =="") {
alert("请输入用户名");
return false;
}
return name;
}
</script>
</form>
</body>
</html>