JS ContextMenu的简单实现
2017-09-17 本文已影响15人
FConfidence
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>contextmenu 鼠标右键</title>
<style>
#contextmenu {
width: 180px;
height: 240px;
background-color: #f2f2f2;
position: absolute;
border: 1px solid #BFBFBF;
box-shadow: 2px 2px 3px #aaaaaa;
}
.show {
display: block;
}
.hidden {
display: none;
}
</style>
</head>
<body>
<script>
(function() {
var menu = document.createElement("div");
menu.id = "contextmenu";
menu.className = "hidden";
document.body.appendChild(menu);
addHandler(document, "contextmenu", function(ev) {
preventDefault(ev);
return false;
});
addHandler(document, "mouseup", openNewContextMenu);
addHandler(document, "mousedown", function(ev) {
menu.className = "hidden";
});
function openNewContextMenu(ev) {
ev = ev || window.event;
var btn = ev.button;
if (btn == 2) {
// menu.style.left = ev.clientX + "px";
// menu.style.top = ev.clientY + "px";
var objPos = getNextContextMenuPostion(ev);
menu.style.left = objPos.left + 'px';
menu.style.top = objPos.top + 'px';
// console.log(getNextContextMenuPostion(ev))
menu.className = "show";
}
}
function preventDefault(event) //阻止事件的默认行为
{
if (event.preventDefault) {
event.preventDefault(); //Chrome FireFox
} else {
event.returnValue = false; //IE
}
}
function addHandler(element, type, handler) {
if (element.addEventListener) { //FireFox Chrome
element.addEventListener(type, handler, false);
} else if (element.attachEvent) { //IE
element.attachEvent("on" + type, handler);
} else {
//使用0级事件
//alert("请更新你的浏览器或者使用谷歌浏览器");
//element.setAttribute("on"+type, handler);
element['on' + type] = handler; //可以这样使用
}
}
function getStyle(obj, attr) {
if (obj.currentStyle) //针对IE浏览器
{
return obj.currentStyle[attr];
} else //针对Firefox
{
return getComputedStyle(obj, false)[attr];
}
/**
* obj.style[attr]只能获取行间样式
* 复合样式: background
* 所以getStyle(obj,"background") 会报错
* 写成 getStyle(obj,"backgroundcolor")
*/
}
function getNextContextMenuPostion(ev) {
var x = ev.clientX,
y = ev.clientY,
html = document.documentElement,
vx = html.clientWidth,
vy = html.clientHeight,
// mw = menu.offsetWidth,
mw = parseInt(getStyle(menu, 'width')),
// mh = menu.offsetHeight;
mh = parseInt(getStyle(menu, 'height'));
// console.log(x+mw, vx)
return {
left: (x + mw) > vx ? (vx - mw - 10) : x,
top: (y + mh) > vy ? (vy - mh - 10) : y
};
}
})();
</script>
</body>
</html>
