Detailed explanation of how the bootstrap fileinput plug-in implements the function of previewing and uploading photos

本文主要介绍了bootstrap fileinput插件实现预览上传照片功能,代码简单易懂，非常不错，具有参考借鉴价值，需要的朋友可以参考下，希望能帮助到大家。

 效果图如下所示：

具体代码如下：

 
  
  
  
  
  
  
  
 

 
  

   

    

     

      
     
     

     

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bootstrap-fileinput.css文件：（github目前正在维护中，之后所有代码上传至我的github）

/*!
 * Jasny Bootstrap v3.1.3 (http://jasny.github.io/bootstrap)
 * Copyright 2012-2014 Arnold Daniels
 * Licensed under Apache-2.0 (https://github.com/jasny/bootstrap/blob/master/LICENSE)
 */
.btn-file {
 position: relative;
 overflow: hidden;
 vertical-align: middle;
}
.btn-file > input {
 position: absolute;
 top: 0;
 right: 0;
 width: 100%;
 height: 100%;
 margin: 0;
 font-size: 23px;
 cursor: pointer;
 filter: alpha(opacity=0);
 opacity: 0;
 direction: ltr;
}
.fileinput {
 display: inline-block;
 margin-bottom: 9px;
}
.fileinput .form-control {
 display: inline-block;
 padding-top: 7px;
 padding-bottom: 5px;
 margin-bottom: 0;
 vertical-align: middle;
 cursor: text;
}
.fileinput .thumbnail {
 display: inline-block;
 margin-bottom: 5px;
 overflow: hidden;
 text-align: center;
 vertical-align: middle;
}
.fileinput .thumbnail > img {
 max-height: 100%;
}
.fileinput .btn {
 vertical-align: middle;
}
.fileinput-exists .fileinput-new,
.fileinput-new .fileinput-exists {
 display: none;
}
.fileinput-inline .fileinput-controls {
 display: inline;
}
.fileinput-filename {
 display: inline-block;
 overflow: hidden;
 vertical-align: middle;
}
.form-control .fileinput-filename {
 vertical-align: bottom;
}
.fileinput.input-group {
 display: table;
}
.fileinput.input-group > * {
 position: relative;
 z-index: 2;
}
.fileinput.input-group > .btn-file {
 z-index: 1;
}
.fileinput-new.input-group .btn-file,
.fileinput-new .input-group .btn-file {
 border-radius: 0 4px 4px 0;
}
.fileinput-new.input-group .btn-file.btn-xs,
.fileinput-new .input-group .btn-file.btn-xs,
.fileinput-new.input-group .btn-file.btn-sm,
.fileinput-new .input-group .btn-file.btn-sm {
 border-radius: 0 3px 3px 0;
}
.fileinput-new.input-group .btn-file.btn-lg,
.fileinput-new .input-group .btn-file.btn-lg {
 border-radius: 0 6px 6px 0;
}
.form-group.has-warning .fileinput .fileinput-preview {
 color: #8a6d3b;
}
.form-group.has-warning .fileinput .thumbnail {
 border-color: #faebcc;
}
.form-group.has-error .fileinput .fileinput-preview {
 color: #a94442;
}
.form-group.has-error .fileinput .thumbnail {
 border-color: #ebccd1;
}
.form-group.has-success .fileinput .fileinput-preview {
 color: #3c763d;
}
.form-group.has-success .fileinput .thumbnail {
 border-color: #d6e9c6;
}
.input-group-addon:not(:first-child) {
 border-left: 0;
}
bootstrap-fileinput.js:
/* ===========================================================
 * Bootstrap: fileinput.js v3.1.3
 * http://jasny.github.com/bootstrap/javascript/#fileinput
 * ===========================================================
 * Copyright 2012-2014 Arnold Daniels
 *
 * Licensed under the Apache License, Version 2.0 (the "License")
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ========================================================== */
+function ($) { "use strict";
 var isIE = window.navigator.appName == 'Microsoft Internet Explorer'
 // FILEUPLOAD PUBLIC CLASS DEFINITION
 // =================================
 var Fileinput = function (element, options) {
 this.$element = $(element)
 this.$input = this.$element.find(':file')
 if (this.$input.length === 0) return
 this.name = this.$input.attr('name') || options.name
 this.$hidden = this.$element.find('input[type=hidden][name="' + this.name + '"]')
 if (this.$hidden.length === 0) {
  this.$hidden = $('').insertBefore(this.$input)
 }
 this.$preview = this.$element.find('.fileinput-preview')
 var height = this.$preview.css('height')
 if (this.$preview.css('display') !== 'inline' && height !== '0px' && height !== 'none') {
  this.$preview.css('line-height', height)
 }
 this.original = {
  exists: this.$element.hasClass('fileinput-exists'),
  preview: this.$preview.html(),
  hiddenVal: this.$hidden.val()
 }
 this.listen()
 }
 Fileinput.prototype.listen = function() {
 this.$input.on('change.bs.fileinput', $.proxy(this.change, this))
 $(this.$input[0].form).on('reset.bs.fileinput', $.proxy(this.reset, this))
 this.$element.find('[data-trigger="fileinput"]').on('click.bs.fileinput', $.proxy(this.trigger, this))
 this.$element.find('[data-dismiss="fileinput"]').on('click.bs.fileinput', $.proxy(this.clear, this))
 },
 Fileinput.prototype.change = function(e) {
 var files = e.target.files === undefined ? (e.target && e.target.value ? [{ name: e.target.value.replace(/^.+\\/, '')}] : []) : e.target.files
 e.stopPropagation()
 if (files.length === 0) {
  this.clear()
  return
 }
 this.$hidden.val('')
 this.$hidden.attr('name', '')
 this.$input.attr('name', this.name)
 var file = files[0]
 if (this.$preview.length > 0 && (typeof file.type !== "undefined" ? file.type.match(/^image\/(gif|png|jpeg)$/) : file.name.match(/\.(gif|png|jpe?g)$/i)) && typeof FileReader !== "undefined") {
  var reader = new FileReader()
  var preview = this.$preview
  var element = this.$element
  reader.onload = function(re) {
  var $img = $('')
  $img[0].src = re.target.result
  files[0].result = re.target.result
  element.find('.fileinput-filename').text(file.name)
  // if parent has max-height, using `(max-)height: 100%` on child doesn't take padding and border into account
  if (preview.css('max-height') != 'none') $img.css('max-height', parseInt(preview.css('max-height'), 10) - parseInt(preview.css('padding-top'), 10) - parseInt(preview.css('padding-bottom'), 10) - parseInt(preview.css('border-top'), 10) - parseInt(preview.css('border-bottom'), 10))
  preview.html($img)
  element.addClass('fileinput-exists').removeClass('fileinput-new')
  element.trigger('change.bs.fileinput', files)
  }
  reader.readAsDataURL(file)
 } else {
  this.$element.find('.fileinput-filename').text(file.name)
  this.$preview.text(file.name)
  this.$element.addClass('fileinput-exists').removeClass('fileinput-new')
  this.$element.trigger('change.bs.fileinput')
 }
 },
 Fileinput.prototype.clear = function(e) {
 if (e) e.preventDefault()
 this.$hidden.val('')
 this.$hidden.attr('name', this.name)
 this.$input.attr('name', '')
 //ie8+ doesn't support changing the value of input with type=file so clone instead
 if (isIE) { 
  var inputClone = this.$input.clone(true);
  this.$input.after(inputClone);
  this.$input.remove();
  this.$input = inputClone;
 } else {
  this.$input.val('')
 }
 this.$preview.html('')
 this.$element.find('.fileinput-filename').text('')
 this.$element.addClass('fileinput-new').removeClass('fileinput-exists')
 if (e !== undefined) {
  this.$input.trigger('change')
  this.$element.trigger('clear.bs.fileinput')
 }
 },
 Fileinput.prototype.reset = function() {
 this.clear()
 this.$hidden.val(this.original.hiddenVal)
 this.$preview.html(this.original.preview)
 this.$element.find('.fileinput-filename').text('')
 if (this.original.exists) this.$element.addClass('fileinput-exists').removeClass('fileinput-new')
  else this.$element.addClass('fileinput-new').removeClass('fileinput-exists')
 this.$element.trigger('reset.bs.fileinput')
 },
 Fileinput.prototype.trigger = function(e) {
 this.$input.trigger('click')
 e.preventDefault()
 }
 // FILEUPLOAD PLUGIN DEFINITION
 // ===========================
 var old = $.fn.fileinput
 $.fn.fileinput = function (options) {
 return this.each(function () {
  var $this = $(this),
   data = $this.data('bs.fileinput')
  if (!data) $this.data('bs.fileinput', (data = new Fileinput(this, options)))
  if (typeof options == 'string') data[options]()
 })
 }
 $.fn.fileinput.Constructor = Fileinput
 // FILEINPUT NO CONFLICT
 // ====================
 $.fn.fileinput.noConflict = function () {
 $.fn.fileinput = old
 return this
 }
 // FILEUPLOAD DATA-API
 // ==================
 $(document).on('click.fileinput.data-api', '[data-provides="fileinput"]', function (e) {
 var $this = $(this)
 if ($this.data('bs.fileinput')) return
 $this.fileinput($this.data())
 var $target = $(e.target).closest('[data-dismiss="fileinput"],[data-trigger="fileinput"]');
 if ($target.length > 0) {
  e.preventDefault()
  $target.trigger('click.bs.fileinput')
 }
 })
}(window.jQuery);

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