最简单的给元素设置事件监听的方法就是设置他们的on...属性，
例如：
window.onload = function(){
};
鼠标事件监听
| 时间名 | 事件描述 |
|---|
| onclick | 当鼠标单击某个对象 |
| ondblclick | 当鼠标双击某个对象 |
| onmousedown | 当某个鼠标按键在某个对象上被按下 |
| onmouseup | 当某个鼠标按键在某个对象被上松开 |
| onmousemove | 当某个鼠标按键在某个对象上被移动 |
| onmouseenter | 当鼠标进入某个对象（相似事件onmouseover) |
| onmouseleave | 当鼠标离开某个对象（相似事件onmouseout) |
案例演示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
width:200px;
height:200px;
background-color:#ccc;
}
</style>
</head>
<body>
<div id="box"></div>
<script>
var oBox = document.getElementById('box');
// 给box这个盒子添加点击事件监听
oBox.onclick = function() {
console.log('我是onclick');
};
oBox.ondblclick = function() {
console.log('我是ondblclick');
};
oBox.onmousedown = function() {
console.log('我是onmousedown');
};
oBox.onmouseup = function() {
console.log('我是onmouseup');
};
oBox.onmouseenter = function() {
console.log('我是onmouseenter');
};
oBox.onmouseleave = function() {
console.log('我是onmouseleave');
};
oBox.onmousemove = function() {
console.log('我是onmousemove');
};
</script>
</body>
</html>
键盘事件监听
| 事件名 | 事件描述 |
|---|
| onkeypress | 当某个键盘的键被按下（系统按钮如箭头键和功能键无法得到识别） |
| onkeydown | 当某个键盘的的键被按下（系统按钮可以识别，并且会先于onkeypress发生） |
| onkeyup | 当某键盘的键被松开 |
案例演示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
姓名：
<input type="text" id = "nameField">
<script>
var nameField = document.getElementById('nameField');
nameField.onkeydown = function () {
console.log('我是onkeydown');
};
nameField.onkeypress = function () {
console.log('我是onkeypress');
};
nameField.onkeyup = function () {
console.log('我是onkeyup');
};
</script>
</body>
</html>
表单事件监听
| 事件名 | 事件描述 |
|---|
| onchange | 当用户改变域的内容 |
| onfocus | 当某元素获得焦点（比如tab键或鼠标点击） |
| onblur | 当某元素失去焦点 |
| onsubmit | 当表单被提交 |
| onreset | 当表单被重置 |
案例演示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<form action="" id="myform">
<p>
姓名：
<input type="text" name="nameField">
</p>
<p>
年龄：
<input type="text" name="ageField">
</p>
<p>
<input type="submit">
<input type="reset">
</p>
</form>
<script>
var myform = document.getElementById("myform");
// 可以直接通过name属性值myform.nameField，打点调用，不用设置id
var nameField = myform.nameField;
var ageField = myform.ageField;
nameField.onchange = function() {
console.log('你已经修改完姓名');
};
nameField.oninput = function() {
console.log('你正在修改完姓名');
};
nameField.onfocus = function() {
console.log('姓名框得到焦点');
};
nameField.onblur = function() {
console.log('姓名框失去焦点');
};
myform.onsubmit = function() {
alert('表单提交');
};
myform.onreset = function() {
alert('重置表单')
}
</script>
</body>
</html>
页面事件监听
| 事件名 | 事件描述 |
|---|
| onload | 当页面或图像被完成加载 |
| onunload | 当用户退出页面 |
案例演示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script>
// 给window对象添加onload事件监听、、onload表示页面都加载完毕了
window.onload = function(){
// 得到盒子1
var box1 = document.getElementById('box1');
// 得到盒子2
var box2 = document.getElementById('box2');
console.log(box1);
console.log(box2);
};
</script>
</head>
<body>
<div id="box1">我是盒子1</div>
<div id="box2">我是盒子2</div>
</body>
</html>
