JS实现多图预览上传的实例代码

/**
 * Created by liujing on 2017/5/10.
 */
$(document).ready(function($) {
  function changef(which,bulk,name_n){
    var bulka = bulk;
    var thisid = which.attr("id");
    var f = which.prop ('files')[0];
    var filename = f.name;
    var mime = filename.toLowerCase().substr(filename.lastIndexOf("."));
    var liid = $("#"+thisid).closest("li").attr("id");
    var liidb = parseInt(liid)+1;
    if(mime==".jpg" || mime==".png"){
      var src = window.URL.createObjectURL(f);
      var name = $("#logo"+liid).val().split("\").pop();
      $('#logotips'+liid).css({"background":'url('+src+')','backgroundSize':100+'%'});
      $('#up_flower'+liid).empty().append(name);
      $('#'+liid).append('<a class="edit_text">✖</a>');
      bulka.append('<li class="uploading" id="'+liidb+'"><a class="a_a" id="logotips'+liidb+'"><input class="input_hide logo'+liidb+'" type="file" name="'+name_n+'" id="logo'+liidb+'"></a></li>');
      $('#logotips'+liidb).css({"background":'url("../../img/c_up.png")','backgroundSize':100+'%'});
    }
    $('.logo'+liid).addClass("newc"+liid);
    $('.newc'+liid).removeClass("logo"+liid);
    $('.newc'+liid).on('change',function(){
      var files = $(this).prop('files')[0];
      var srcb = window.URL.createObjectURL(files);
      var liid = $("#"+thisid).closest("li").attr("id");
      var liidb = parseInt(liid)+1;
      var name = $("#logo"+liid).val().split("\").pop();
      $('#logotips'+liid).css({"background":'url('+srcb+')','backgroundSize':100+'%'});
      $('#up_flower'+liid).empty().append(name);
    })
    $('.edit_text').on('click',function(){
      $(this).parent().remove();
    })
  } 
  function changelast(which ,bulk){
    var bulka = bulk;
    var thisid = which.attr("id");
    var f = which.prop ('files')[0];
    var filename = f.name;
    var mime = filename.toLowerCase().substr(filename.lastIndexOf("."));
    var liid = $("#"+thisid).closest("li").attr("id");
    var liidb = parseInt(liid)+1;
    if(mime==".jpg" || mime==".png"){
      var src = window.URL.createObjectURL(f);
      var name = $("#logo"+liid).val().split("\").pop();
      $('#logotips'+liid).css({"background":'url('+src+')','backgroundSize':100+'%'});
      $('#up_flower'+liid).empty().append(name);
      $('#'+liid).append('<a class="edit_text">✖</a>');
    }
    $('.logo'+liid).addClass("newc"+liid);
    $('.newc'+liid).removeClass("logo"+liid);
    $('.newc'+liid).on('change',function(){
      var files = $(this).prop('files')[0];
      var srcb = window.URL.createObjectURL(files);
      var liid = $("#"+thisid).closest("li").attr("id");
      var liidb = parseInt(liid)+1;
      var name = $("#logo"+liid).val().split("\").pop();
      $('#logotips'+liid).css({"background":'url('+srcb+')','backgroundSize':100+'%'});
      $('#up_flower'+liid).empty().append(name);
    })
    $('.edit_text').on('click',function(){
      $(this).parent().remove();
    })
  } 
    $(".logo1").one("change",function(){
      that = $(this); var bulk = $("#add_beo"); var name = $(this).attr('name'); changef(that,bulk,name);
    });
    $("#add_beo").one("change",".logo2",function(){
      that = $(this); var bulk = $("#add_beo"); var name = $(this).attr('name'); changef(that,bulk,name);
    });
    $("#add_beo").one("change",".logo3",function(){
      that = $(this); var bulk = $("#add_beo"); var name = $(this).attr('name'); changef(that,bulk,name);
    });
    $("#add_beo").one("change",".logo4",function(){
      that = $(this); var bulk = $("#add_beo"); var name = $(this).attr('name'); changef(that,bulk,name);
    });
    $("#add_beo").one("change",".logo5",function(){
      that = $(this); var bulk = $("#add_beo"); changelast(that , bulk);
    });
});