背景：頁面上一個按鈕，點選彈出上傳框，從按鈕的方法程式碼開始寫：處理未選擇檔案阻止上傳；通過判斷選擇檔案的數量，顯示或隱藏上傳按鈕；
在js中定義： function uploadFile(){
layer.open({
type:1,
title:'上傳檔案‘,
area:['25%','400px'],
content:'<div class="layui-form-item" style="margin-top:40px;">\
<div class="layui-input-block">\
<input class="layui-btn" type="button" id="chooseFIle" value="選擇檔案">\
<span></span>\
</div>\
</div>\
<div class="layui-form-item" style="margin-top:40px;">\
<div class="layui-input-block">\
<input class="layui-btn" type="button" id="uploadbtn" value="上傳">\
<span></span>\
</div>\
</div>‘，
btn:['關閉'],
btn1:function(idx,ele){
layer.closeAll();
}
})
createUpload();
}
var files ;
function createUpload(){
$("#uploadbtn").hide();
$("#chooseFile").next().next("span").text("");
layui.use(['upload'],function(){
var uploadInst = upload.render({
elem:'#chooseFile',
url:' ',
accept:'file',
auto:false,
multiple:true,
acceptMime:'application/vnd.ms-excel,application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
exts:'xls|xlsx',
size:1024000,
number:5,
bindAction:'#uploadbtn',
choose:function(obj){
files = this.files = boj.pushFile();
if(Object.keys(files).length>0){ $("#uploadbtn").show(); }
obj.preview(function(index,file,result){
$("#chooseFile").siblings("span").append("<div title='"+index+"'>"+file.name+" <span onclick='deletefile(\""+index+"\")'>×</span></div>")
if(index>0) {$("#uploadbtn").show() ;}
})
},
allDone:function(obj){
if(obj.successful){
layer.msg(obj.total+"個檔案上傳成功!");
}
},
error:function(){
layer.alert("上傳成功!");
}
})
}
}
function deletefile(index){
delete files[index];
$("#chooseFile").siblings("span").find("div[title="+index+"]").remove();
if(!Object.keys(files).length>0){
$("#uploadbtn").hide();
}
}