一、阻止默认行为：
return false；
例如：屏蔽右键菜单，弹出自定义右键菜单
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
* {
margin: 0;
padding: 0;
list-style: none;
}
#div1 {
width: 80px;
background: #ccc;
position: absolute;
display: none;
}
</style>
<script>
document.oncontextmenu = function (ev) {
oEvent = ev || event;
var oDiv = document.getElementById(‘div1‘);
oDiv.style.display = ‘block‘;
//div的位置跟着鼠标的位置出现
oDiv.style.left = oEvent.clientX + ‘px‘;
oDiv.style.top = oEvent.clientY + ‘px‘;
return false;//屏蔽右键默认菜单
};
//点击空白取消自定义菜单
document.onclick = function () {
var oDiv = document.getElementById(‘div1‘);
oDiv.style.display = ‘none‘;
};
</script>
</head>
<body>
<div id="div1">
<ul>
<li>aaaa</li>
<li>bbbb</li>
<li>cccc</li>
<li>dddd</li>
</ul>
</div>
</body>
</html>
二、只能输入数字的输入框 （在英文输入状态下）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
</style>
<script>
window.onload = function () {
var oText1 = document.getElementById(‘text1‘);
oText1.onkeydown = function (ev) {
var oEvent = ev || event;
//只能输入数字的输入框 0为48，9为57，删除键为8
if(oEvent.keyCode!= 8 &&(oEvent.keyCode<48||oEvent.keyCode>57)){
return false;//不为数字不能输入
}
};
};
</script>
</head>
<body>
<input type="text" id="text1">
</body>
</html>
时间： 2024-10-09 21:39:35