select实现多选下拉框功能（excel下拉框实现复选）
各位朋友大家早上好！
今天给大家带来的是 八种select下拉选择特效源码！
在日常工作中会经常遇到！
大家可以按照自己的意愿，做成喜欢的样子！
有想要文件版源码的可以私聊小编！
废话不多说，上源码！
JS:
/**
* selectFx.js v1.0.0
* http://www.codrops.com
*
* Licensed under the MIT license.
* http://www.opensource.org/licenses/mit-license.php
*
* Copyright 2014, Codrops
* http://www.codrops.com
*/
;( function( window ) {
‘use strict’;
/**
* based on from https://github.com/inuyaksa/jquery.nicescroll/blob/master/jquery.nicescroll.js
*/
function hasParent( e, p ) {
if (!e) return false;
var el = e.target||e.srcElement||e||false;
while (el && el != p) {
el = el.parentNode||false;
}
return (el!==false);
};
/**
* extend obj function
*/
function extend( a, b ) {
for( var key in b ) {
if( b.hasOwnProperty( key ) ) {
a[key] = b[key];
}
}
return a;
}
/**
* SelectFx function
*/
function SelectFx( el, options ) {
this.el = el;
this.options = extend( {}, this.options );
extend( this.options, options );
this._init();
}
/**
* SelectFx options
*/
SelectFx.prototype.options = {
// if true all the links will open in a new tab.
// if we want to be redirected when we click an option, we need to define a data-link attr on the option of the native select element
newTab : true,
// when opening the select element, the default placeholder (if any) is shown
stickyPlaceholder : true,
// callback when changing the value
onChange : function( val ) { return false; }
}
/**
* init function
* initialize and cache some vars
*/
SelectFx.prototype._init = function() {
// check if we are using a placeholder for the native select box
// we assume the placeholder is disabled and selected by default
var selectedOpt = this.el.querySelector( ‘option[selected]’ );
this.hasDefaultPlaceholder = selectedOpt && selectedOpt.disabled;
// get selected option (either the first option with attr selected or just the first option)
this.selectedOpt = selectedOpt || this.el.querySelector( ‘option’ );
// create structure
this._createSelectEl();
// all options
this.selOpts = [].slice.call( this.selEl.querySelectorAll( ‘li[data-option]’ ) );
// total options
this.selOptsCount = this.selOpts.length;
// current index
this.current = this.selOpts.indexOf( this.selEl.querySelector( ‘li.cs-selected’ ) ) || -1;
// placeholder elem
this.selPlaceholder = this.selEl.querySelector( ‘span.cs-placeholder’ );
// init events
this._initEvents();
}
/**
* creates the structure for the select element
*/
SelectFx.prototype._createSelectEl = function() {
var self = this, options = ”, createOptionHTML = function(el) {
var optclass = ”, classes = ”, link = ”;
if( el.selectedOpt && !this.foundSelected && !this.hasDefaultPlaceholder ) {
classes += ‘cs-selected ‘;
this.foundSelected = true;
}
// extra classes
if( el.getAttribute( ‘data-class’ ) ) {
classes += el.getAttribute( ‘data-class’ );
}
// link options
if( el.getAttribute( ‘data-link’ ) ) {
link = ‘data-link=’ + el.getAttribute( ‘data-link’ );
}
if( classes !== ” ) {
optclass = ‘class=”‘ + classes + ‘” ‘;
}
return ‘
};
[].slice.call( this.el.children ).forEach( function(el) {
if( el.disabled ) { return; }
var tag = el.tagName.toLowerCase();
if( tag === ‘option’ ) {
options += createOptionHTML(el);
}
else if( tag === ‘optgroup’ ) {
options += ‘
- ’;
[].slice.call( el.children ).forEach( function(opt) {
options += createOptionHTML(opt);
} )
options += ‘
}
} );
var opts_el = ‘
’;this.selEl = document.createElement( ‘div’ );
this.selEl.className = this.el.className;
this.selEl.tabIndex = this.el.tabIndex;
this.selEl.innerHTML = ‘’ + this.selectedOpt.textContent + ‘’ + opts_el;
this.el.parentNode.appendChild( this.selEl );
this.selEl.appendChild( this.el );
}
/**
* initialize the events
*/
SelectFx.prototype._initEvents = function() {
var self = this;
// open/close select
this.selPlaceholder.addEventListener( ‘click’, function() {
self._toggleSelect();
} );
// clicking the options
this.selOpts.forEach( function(opt, idx) {
opt.addEventListener( ‘click’, function() {
self.current = idx;
self._changeOption();
// close select elem
self._toggleSelect();
} );
} );
// close the select element if the target it´s not the select element or one of its descendants..
document.addEventListener( ‘click’, function(ev) {
var target = ev.target;
if( self._isOpen() && target !== self.selEl && !hasParent( target, self.selEl ) ) {
self._toggleSelect();
}
} );
// keyboard navigation events
this.selEl.addEventListener( ‘keydown’, function( ev ) {
var keyCode = ev.keyCode || ev.which;
switch (keyCode) {
// up key
case 38:
ev.preventDefault();
self._navigateOpts(‘prev’);
break;
// down key
case 40:
ev.preventDefault();
self._navigateOpts(‘next’);
break;
// space key
case 32:
ev.preventDefault();
if( self._isOpen() && typeof self.preSelCurrent != ‘undefined’ && self.preSelCurrent !== -1 ) {
self._changeOption();
}
self._toggleSelect();
break;
// enter key
case 13:
ev.preventDefault();
if( self._isOpen() && typeof self.preSelCurrent != ‘undefined’ && self.preSelCurrent !== -1 ) {
self._changeOption();
self._toggleSelect();
}
break;
// esc key
case 27:
ev.preventDefault();
if( self._isOpen() ) {
self._toggleSelect();
}
break;
}
} );
}
/**
* navigate with up/dpwn keys
*/
SelectFx.prototype._navigateOpts = function(dir) {
if( !this._isOpen() ) {
this._toggleSelect();
}
var tmpcurrent = typeof this.preSelCurrent != ‘undefined’ && this.preSelCurrent !== -1 ? this.preSelCurrent : this.current;
if( dir === ‘prev’ && tmpcurrent > 0 || dir === ‘next’ && tmpcurrent < this.selOptsCount – 1 ) {
// save pre selected current – if we click on option, or press enter, or press space this is going to be the index of the current option
this.preSelCurrent = dir === ‘next’ ? tmpcurrent + 1 : tmpcurrent – 1;
// remove focus class if any..
this._removeFocus();
// add class focus – track which option we are navigating
classie.add( this.selOpts[this.preSelCurrent], ‘cs-focus’ );
}
}
/**
* open/close select
* when opened show the default placeholder if any
*/
SelectFx.prototype._toggleSelect = function() {
// remove focus class if any..
this._removeFocus();
if( this._isOpen() ) {
if( this.current !== -1 ) {
// update placeholder text
this.selPlaceholder.textContent = this.selOpts[ this.current ].textContent;
}
classie.remove( this.selEl, ‘cs-active’ );
}
else {
if( this.hasDefaultPlaceholder && this.options.stickyPlaceholder ) {
// everytime we open we wanna see the default placeholder text
this.selPlaceholder.textContent = this.selectedOpt.textContent;
}
classie.add( this.selEl, ‘cs-active’ );
}
}
/**
* change option – the new value is set
*/
SelectFx.prototype._changeOption = function() {
// if pre selected current (if we navigate with the keyboard)…
if( typeof this.preSelCurrent != ‘undefined’ && this.preSelCurrent !== -1 ) {
this.current = this.preSelCurrent;
this.preSelCurrent = -1;
}
// current option
var opt = this.selOpts[ this.current ];
// update current selected value
this.selPlaceholder.textContent = opt.textContent;
// change native select element´s value
this.el.value = opt.getAttribute( ‘data-value’ );
// remove class cs-selected from old selected option and add it to current selected option
var oldOpt = this.selEl.querySelector( ‘li.cs-selected’ );
if( oldOpt ) {
classie.remove( oldOpt, ‘cs-selected’ );
}
classie.add( opt, ‘cs-selected’ );
// if there´s a link defined
if( opt.getAttribute( ‘data-link’ ) ) {
// open in new tab?
if( this.options.newTab ) {
window.open( opt.getAttribute( ‘data-link’ ), ‘_blank’ );
}
else {
window.location = opt.getAttribute( ‘data-link’ );
}
}
// callback
this.options.onChange( this.el.value );
}
/**
* returns true if select element is opened
*/
SelectFx.prototype._isOpen = function(opt) {
return classie.has( this.selEl, ‘cs-active’ );
}
/**
* removes the focus class from the option
*/
SelectFx.prototype._removeFocus = function(opt) {
var focusEl = this.selEl.querySelector( ‘li.cs-focus’ )
if( focusEl ) {
classie.remove( focusEl, ‘cs-focus’ );
}
}
/**
* add to global namespace
*/
window.SelectFx = SelectFx;
} )( window );