js 编写插件（上传图片）

upload.js
/**

定义上传控件组件，需要依赖jQuery插件

created by dake 2018/10/22
*/
(function ( $) { function DragImgUpload(id,options) { this.me =$ (id);
var defaultOpt = {
boxWidth:'200px',
boxHeight:'200px'
}
this.preview = $('<div id="preview"><img src="img/upload.png" class="img-responsive" style="width: 100%;height: auto;" alt="" title=""> </div>'); this.opts=$ .extend(true, defaultOpt,{
}, options);
this.init();
this.callback = this.opts.callback;
}

//定义原型方法
DragImgUpload.prototype = {
constructor: DragImgUpload,
init:function () {
this.me.append(this.preview);
this.cssInit();
this.eventClickInit();
},
cssInit:function () {
this.me.css({
'width':this.opts.boxWidth,
'height':this.opts.boxHeight,
'border':'2px solid #cccccc',
'padding':'10px',
'cursor':'pointer'
})
this.preview.css({
'height':'100%',
'overflow':'hidden'
})

 },
 onDragover:function (e) {
     e.stopPropagation();
     e.preventDefault();
     e.dataTransfer.dropEffect = 'copy';
 },
 onDrop:function (e) {
     var self = this;
     e.stopPropagation();
     e.preventDefault();
     var fileList = e.dataTransfer.files; //获取文件对象
     // do something upload
     if(fileList.length == 0){
         return false;
     }
     //检测文件是不是图片
     if(fileList[0].type.indexOf('image') === -1){
         alert("您拖的不是图片！");
         return false;
     }

     //拖拉图片到浏览器，可以实现预览功能
     var img = window.URL.createObjectURL(fileList[0]);
     var filename = fileList[0].name; //图片名称
     var filesize = Math.floor((fileList[0].size)/1024);
     if(filesize>500){
         alert("上传大小不能超过500K.");
         return false;
     }

     self.me.find("img").attr("src",img);
     self.me.find("img").attr("title",filename);
     if(this.callback){
         this.callback(fileList);
     }
 },
 eventClickInit:function () {
     var self = this;
     this.me.unbind().click(function () {
         self.createImageUploadDialog();
     })
     var dp = this.me[0];
     dp.addEventListener('dragover', function(e) {
         self.onDragover(e);
     });
     dp.addEventListener("drop", function(e) {
         self.onDrop(e);
     });


 },
 onChangeUploadFile:function () {
     var fileInput = this.fileInput;
     var files = fileInput.files;
     var file = files[0];
     var img = window.URL.createObjectURL(file);
     var filename = file.name;
     this.me.find("img").attr("src",img);
     this.me.find("img").attr("title",filename);
     if(this.callback){
         this.callback(files);
     }
 },
 createImageUploadDialog:function () {
     var fileInput = this.fileInput;
     if (!fileInput) {
         //创建临时input元素
         fileInput = document.createElement('input');
         //设置input type为文件类型
         fileInput.type = 'file';
         //设置文件name
         fileInput.name = 'ime-images';
         //允许上传多个文件
         fileInput.multiple = true;
         fileInput.onchange  = this.onChangeUploadFile.bind(this);
         this.fileInput = fileInput;
     }
     //触发点击input点击事件，弹出选择文件对话框
     fileInput.click();
 }

}
//初始化组件方法
$.fn.dragImgUpload = function (option) { console.log("create component..."); return this.each(function () { //防止初始化过了还需要初始化 var$ this = $(this), data =$ this.data('dragImgupload'),
options = typeof option === 'object' && option;
if (!data) {
$this.data('dragImgupload', (data = new DragImgUpload(this,options))); } if (typeof option == 'string') { data[option](); } }) }$ .fn.dragImgUpload.Constructor = DragImgUpload;

})(window.jQuery);

2.初始化
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<style type="text/css">

</style>
<script src="jquery.js"></script>
<script src="upload.js"></script>
<body>
<div id="drop_area" class="aaa"></div>

</body>
<script type="text/javascript">
var dragImgUpload =$("#drop_area").dragImgUpload({
callback:function (files) {
//回调函数，可以传递给后台等等
var file = files[0];
console.log(file.name);
}
})
console.log(dragImgUpload);
</script>
</html>

js 编写插件 （上传图片）

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js 编写插件（上传图片）