js下拉菜单生成器dropMenu使用方法详解

时间：2019-01-07分类：JavaScript作者：编程之家用户

本文实例为大家分享了下拉菜单生成器dropMenu的使用方法，供大家参考，具体内容如

HTML

职级：

function partyLabel(menuID,data){
new DropMeun({
'id':menuID,"data":data,"dataSrc":"name",//数据是下面的这种格式的，你要的是name的值
"ableSearch":true,//可以搜索
"style":{ //样式，可选
"width":173,"maxHeight":200,"left":0,//定位到哪里
"top":5,"initPos":"left" //设置在哪边出现
}
})
}

3.在页面中引用一个js 文件

/-- tools --/

function getRealTop(node) {
return node.offsetParent.tagName.toUpperCase() === 'BODY' ?
node.offsetTop :
node.offsetTop + arguments.callee(node.offsetParent)
}

function getRealLeft(node) {
return node.offsetParent.tagName.toUpperCase() === 'BODY' ?
node.offsetLeft :
node.offsetLeft + arguments.callee(node.offsetParent)
}

/-- tools end--/

function DropMeun(option) {
this.picker = null
this.self = null
this.option = option
this.item = option.item || []
this.style = option.style || {}
this.dataList = option.data || []

this.init()
return this;
}

DropMeun.prototype.init = function () {
var html = '',_this = this

this.self = document.createElement('ul')
this.picker = document.getElementById(this.option.id)

if (! this.picker) {
throw 'picker is null,making sure that picker\'s ID \''+ this.option.id +'\' is correct'
return
}

if (this.option.ableSearch) {
html += '

'
}

this.dataList.forEach(function(data,index) {
var item = _this.option.dataSrc ? data[_this.option.dataSrc] : data,content = _this.item.render ? _this.item.render(item,data) : item

html += '<li class="dropMeun-item '+ (_this.item.className || '') +'" data-index="'+ index +'">'+ content +''
})

this.self.classList.add('dropMeun')
this.self.innerHTML = html
document.body.appendChild(this.self)

this.setStyle()
this.bindEvent()
}

DropMeun.prototype.setStyle = function() {

this.self.style.width =
this.style.width ?
(parseInt(this.style.width) - 26) + 'px' :
'150px'

this.self.style.maxHeight =
this.style.maxHeight ?
(parseInt(this.style.maxHeight) - 26) + 'px' :
'300px'

var w = getRealLeft(this.picker) + (parseInt(this.style.left) || 0)
var h = getRealTop(this.picker) + this.picker.offsetHeight + (parseInt(this.style.top) || 0)

var realWidth = parseInt(this.self.style.width) + 26 // 26 = dobule(padding + border)

if (this.style.initPos === 'right') {
w = w - realWidth + this.picker.offsetWidth
}

this.self.style.top = h + 'px'
this.self.style.left = w + 'px'

}

DropMeun.prototype.bindEvent = function() {
var

_this = this,iEvent = this.picker.nodeName.toUpperCase() !== 'INPUT' ?
'click' :
this.picker.type.toUpperCase() === 'TEXT' ?
'focus' : 'click'

this.picker.addEventListener('click',function(ev) {
var ev = ev || window.ev
ev.stopPropagation()
})

//
this.picker.addEventListener(iEvent,function(ev) {

document.body.click() // 触发 window.click 使其他dropMeun关闭

_this.self.style.display = 'block'
})

//
window.addEventListener('click',function() {
_this.self.style.display = 'none'
})

//
this.self.addEventListener('click',function(ev) {
var ev = ev || window.ev
ev.stopPropagation()

// 事件委托 item点击
if (ev.target.classList.contains('dropMeun-item')) {
var index = parseInt(ev.target.getAttribute('data-index'))
data = _this.option.dataSrc ?
_this.dataList[index][_this.option.dataSrc] :
_this.dataList[index]

if (iEvent === 'focus') {
 _this.picker.value = ev.target.innerText
}

if (_this.item.callbakc) {
_this.item.callbakc(data,_this.picker,_this.dataList[index],_this.dataList)
}

_this.self.style.display = 'none'

}
})
//
if (_this.option.ableSearch) {

_this.searchInput = _this.self.getElementsByClassName('dropMeun-searchInput')[0]

_this.searchInput.addEventListener('keyup',function() {
var target = this.value.trim(),items = _this.self.getElementsByClassName('dropMeun-item');

[].slice.call(items).forEach(function(item,index) {
 item.style.display =
 item.innerText.indexOf(target) === -1 ?
 'none' : ''
})

})
}
}

return DropMeun
}())

4.在页面中引用一个css文件

.dropMeun {
position: absolute;
border: 1px solid #ccc;
overflow: auto;
padding: 8px 12px;
box-shadow: 0 6px 12px rgba(0,.175);
background-color: #fff;
border-bottom-left-radius: 4px;
border-bottom-right-radius: 4px;
box-sizing: content-box;
display: none;
}

.dropMeun li.dropMeun-item {
min-width: 150px;
padding: 2px 2px;
white-space: nowrap;
overflow: hidden;
text-overflow: ellipsis;
}

.dropMeun li.dropMeun-item:hover {
cursor: pointer;
background-color: rgba(238,238,0.8);
}

.dropMeun-searchInput {
outline: none;
width: 100%;
box-sizing: border-box;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程之家。

dropMenu js 下拉菜单

js下拉菜单生成器dropMenu使用方法详解

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