原生js实现简洁的下拉菜单
当前为
此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.gf.qytechs.cn/scripts/463933/1175343/MyDropdown.js
//构造方法
function MyDropdown(options){
//_count是某实例下的菜单个数
this._count = 0;
this._zIndex = 1000;
this._config = options;
window._MyDropdownPosIndex = (window._MyDropdownPosIndex||this._zIndex)+1;
//实例总个数
window._MyDropdownInsCount = (window._MyDropdownInsCount||0)+1;
//当前第几个实例
this.insCount = window._MyDropdownInsCount;
if(this._config) {
this.config(options);
this.createStyle();
}
//返回对象类型
this.type = function(obj) {
return Object.prototype.toString
.call(obj)
.replace(/^\[object (.+)\]$/, '$1')
.toLowerCase();
}
}
MyDropdown.prototype.createStyle = function() {
if(document.querySelector("#MyDropdownStyle")) {
return;
}
let = style = `
<style>
.my-dropdown-wrapper {
display: none;
position: absolute;
background-color: #f1f1f1;
min-width: 160px;
overflow: auto;
box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
z-index: 1;
}
.my-dropdown-wrapper a {
color: black;
padding: 12px 16px;
text-decoration: none;
display: block;
}
.my-dropdown-wrapper a:hover {background-color: #ddd;}
.my-dropdown-wrapper a.selected {background-color: #ddd;}
.show {display: block;}
.my-dropdown-item-icon svg{width: 24px;height: 24px;float: left;}
.close {
width: 24px;
height: 24px;
display: inline-block;
line-height: 24px;
text-align: center;
font-size: 18px;
float: right;
}
</style>
`
document.body.insertAdjacentHTML("beforeend", style);
}
//设置用户配置
MyDropdown.prototype.config = function(options) {
var _this = this;
//设置用户配置
_this._config = options || _this._config;
if(_this._config.toggleEvent && _this._config.toggleEvent.toLowerCase() === 'mouseover') {
_this._config.toggleEvent = 'mouseenter';
}
//绑定事件源按钮点击事件
document.querySelectorAll(_this._config.el||".my-dropdown-btn").forEach(function(item){
item.addEventListener(_this._config.toggleEvent||'click', function(e){
_this.create(this);
_this.show(this);
e.stopPropagation();
return false;
});
});
//点击空白，菜单消失
document.addEventListener('click', function(e){
if (!e.target.matches(_this._config.el||'.my-dropdown-btn')) {
_this.hide();
}
});
}
//创建菜单
MyDropdown.prototype.create = function(objBtn, options) {
var _this = this;
options = options || _this._config;
if(options.el) {
_this._config.el = options.el;
}
if(objBtn) {
if (!objBtn.dataset.count) {
objBtn.dataset.count = _this._count++;
objBtn.classList.add('my-btn'+_this.insCount+objBtn.dataset.count);
}
}
var count = objBtn.dataset.count || 0;
//已存在则返回
if(document.querySelector(`#myDropdownWrapper${_this.insCount}${count}`)) {
return;
}
var mouseenterClass = "";
if(_this._config.toggleEvent && _this._config.toggleEvent.toLowerCase() === 'mouseenter') {
mouseenterClass = " mouseenter";
}
//生成菜单 这里count是某实例下的菜单个数，_this.insCount是实例个数
var menu = `<div id="myDropdownWrapper${_this.insCount}${count}" class="my-dropdown-wrapper${mouseenterClass}" style="overflow:auto;${options.maxWidth?'max-width:'+options.maxWidth+';':''}${options.maxHeight?'max-height:'+options.maxHeight+';':''}" data-count="${count}">`;
if(options.items) {
for(var i in options.items){
var item = options.items[i];
//处理icon选项
var iconHtml = '';
if(item.icon){
if(_this.type(item.icon) === 'object'){
iconHtml = item.icon.html ? item.icon.html : '';
} else {
iconHtml = item.icon ? item.icon : '';
}
}
//处理op选项
var opHtml = '';
if(item.op){
if(_this.type(item.op) === 'object'){
opHtml = item.op.html ? item.op.html : '';
} else {
opHtml = item.op ? item.op : '';
}
}
//生成菜单项
menu += `<a href="javascript:;" class="my-dropdown-item ${item.selected?'selected':''}" data-index="${i}" data-value="${item.value}"><span class="my-dropdown-item-icon">${iconHtml}</span>${item.name}<span class="my-dropdown-item-op">${opHtml}</span></a>`;
}
}
menu += `</div>`;
//追加到body中
document.body.insertAdjacentHTML("beforeend", menu);
//绑定菜单事件
if(_this._config.toggleEvent && _this._config.toggleEvent.toLowerCase() === 'mouseenter') {
//绑定菜单列表
document.querySelector("#myDropdownWrapper" + _this.insCount + count).addEventListener("mouseleave", function(e){
_this.hide(this);
});
}
//绑定菜单item点击事件
document.querySelectorAll("#myDropdownWrapper" + _this.insCount + count + " .my-dropdown-item").forEach(function(item){
item.addEventListener("click", function(e){
if(typeof this.dataset.index !== 'undefined' && options.items[this.dataset.index]) {
options.items[this.dataset.index].fn(e);
}
});
});
//绑定菜单项icon按钮点击事件
document.querySelectorAll("#myDropdownWrapper" + _this.insCount + count + " .my-dropdown-item-icon").forEach(function(item){
//if(!item.innerHTML) return;
item.addEventListener("click", function(e){
if(typeof this.parentElement.dataset.index !== 'undefined' && options.items[this.parentElement.dataset.index] &&
options.items[this.parentElement.dataset.index].icon && options.items[this.parentElement.dataset.index].icon.fn) {
var _this_item = this;
(function(e){
options.items[_this_item.parentElement.dataset.index].icon.fn(e);
e.stopPropagation();
return false;
})(e);
}
});
});
//绑定菜单项操作按钮点击事件
document.querySelectorAll("#myDropdownWrapper" + _this.insCount + count + " .my-dropdown-item-op").forEach(function(item){
//if(!item.innerHTML) return;
item.addEventListener("click", function(e){
if(typeof this.parentElement.dataset.index !== 'undefined' && options.items[this.parentElement.dataset.index] &&
options.items[this.parentElement.dataset.index].op && options.items[this.parentElement.dataset.index].op.fn) {
var _this_item = this;
(function(e){
options.items[_this_item.parentElement.dataset.index].op.fn(e);
e.stopPropagation();
return false;
})(e);
}
});
});
if(options.created) options.created(document.querySelector(`#myDropdownWrapper${_this.insCount}${count}`));
};
//菜单显示
MyDropdown.prototype.show = function(objBtn, callback) {
var count = objBtn.dataset.count || 0;
var myDropdownWrapper = document.getElementById("myDropdownWrapper"+this.insCount+count);
if(objBtn){
myDropdownWrapper.style.top = (objBtn.offsetTop + objBtn.offsetHeight) + "px";
myDropdownWrapper.style.left = objBtn.offsetLeft + "px";
}
if (myDropdownWrapper.classList.contains('show')) {
if(this._config.toggleEvent && this._config.toggleEvent.toLowerCase() === 'mouseenter'){
return;
}
//隐藏菜单
myDropdownWrapper.classList.remove('show');
if(this._config.hidden) this._config.hidden();
} else {
if(this._config.toggleEvent && this._config.toggleEvent.toLowerCase() === 'mouseenter'){
this.hide();
}
//显示菜单
myDropdownWrapper.style.zIndex = window._MyDropdownPosIndex++;
myDropdownWrapper.classList.add('show');
callback = callback || this._config.shown;
if(callback) callback(myDropdownWrapper);
}
//myDropdownWrapper.classList.toggle("show");
}
//菜单隐藏
MyDropdown.prototype.hide = function(objMenu, callback) {
if(objMenu) {
//单个菜单隐藏
if (objMenu.classList.contains('show')) {
objMenu.classList.remove('show');
callback = callback || this._config.hidden;
if(callback) callback(objMenu);
}
} else {
var mouseenterClass = '';
if(this._config.toggleEvent && this._config.toggleEvent.toLowerCase() === 'mouseenter'){
mouseenterClass = ".mouseenter";
}
//所有菜单隐藏
var dropdowns = document.querySelectorAll(".my-dropdown-wrapper" + mouseenterClass);
for (var i = 0; i < dropdowns.length; i++) {
var openDropdown = dropdowns[i];
if (openDropdown.classList.contains('show')) {
openDropdown.classList.remove('show');
callback = callback || this._config.hidden;
if(callback) callback(openDropdown);
}
}
}
};
//使用示例
//测试1
// var clicked = function(e) {
// console.log("clicked", e.target.dataset.value)
// }
// new MyDropdown({
// el: ".my-dropdown-btn",
// maxWidth: '200px',
// maxHeight: '400px',
// //支持click mouseenter dblclick等，默认click
// toggleEvent: 'mouseenter',
// items: [
// {
// name: 'Home',
// value: 'home',
// icon: '',
// fn: clicked
// },
// {
// name: 'About',
// value: 'about',
// icon: '',
// selected: false,
// fn: clicked
// },
// {
// name: 'Contact',
// value: 'contact',
// icon: '',
// fn: clicked,
// //icon也支持对象传值，同样具有html和fn属性
// op: {
// html: `<span class="close">×</span>`,
// fn: function(e) {
// console.log('op clicked');
// }
// }
// }
// ],
// created: function(menu) {
// console.log('After created callback');
// },
// shown: function(menu) {
// console.log('After shown callback');
// },
// hidden: function(menu) {
// console.log('After hidden callback');
// }
// });
// //测试2
// var clicked2 = function(e) {
// console.log("clicked2", e.target.dataset.value)
// }
// new MyDropdown({
// el: ".my-dropdown-btn2",
// items: [
// {
// name: 'Home2',
// value: 'home2',
// icon: '',
// fn: clicked2
// },
// {
// name: 'About2',
// value: 'about2',
// icon: '',
// selected: false,
// fn: clicked2
// },
// {
// name: 'Contact2',
// value: 'contact2',
// icon: '',
// fn: clicked2
// }
// ],
// created: function(menu) {
// console.log('After created callback');
// },
// shown: function(menu) {
// console.log('After shown callback');
// },
// hidden: function(menu) {
// console.log('After hidden callback');
// }
// });
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