js下拉菜单生成器dropMenu使用方法详解

<div class="input-group">
 　　<span class="input-group-addon" style="width: 100px" >职级：</span>
  <input type="text" class="units form-control" id="jobTitle" value="其他" style="border-radius:0 4px 4px 0;"></input>
  <span class="caret beside"></span>
</div>

$(function(){
 var title,
 populationType,
 titleInParty;
 $.ajax({
  url:'/api/v1/user/getUserTypeInfo',
  type:'GET',
  dataType:'json',
  success:function (data) {
   title=data.data.title;
   titleInParty=data.data.titleInParty;
   populationType=data.data.populationType;
   partyLabel('jobTitle',title);
   partyLabel('populationType',populationType);
   partyLabel('titleInParty',titleInParty);
  }
 });

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
   }
  })
 }

(function(vq0599) {
 window.DropMeun = vq0599
})(function() {

 /*-- 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 += '<li><input class="dropMeun-searchInput" type="text"></li>'
    }

    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 +'</li>'
    })

    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
}())

ul,
li {
  list-style: none;
  margin: 0;
  padding: 0;
}

.dropMeun {
  position: absolute;
  border: 1px solid #ccc;
  overflow: auto;
  padding: 8px 12px;
  box-shadow: 0 6px 12px rgba(0, 0, 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, 238, 0.8);
}

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