JavaScript对上传文件相关操作

JS

window.onload = function(){
	uploadCount = 1;//增加的文件“input”标示符

	isIE = function(){//是否是ie
		return document.all ? true : false;
	}

	getFileSize = function(_f){//获取文件大小
		var _fileSize = 0;
		if (this.isIE() && !_f.files) {
			var filePath = _f.value;
			var fileSystem = new ActiveXObject("Scripting.FileSystemObject");

			if(!fileSystem.FileExists(filePath)){
				return 0;
			}
			var file = fileSystem.GetFile (filePath);
			_fileSize = file.Size;
		} else {
			_fileSize = (_f.files[0] && _f.files[0].size) || 0;
		}
		return _fileSize;
	}

	fileType = function(_eForm, types){//限制上传文件的格式
		var _elements = _eForm.elements,
				_elementsLen = _elements.length
		_ei = null,
				_v = "",
				_contentType = "",
				i = 0;
		for (; i < _elementsLen ; i++){
			_ei = _elements[i];
			if(_ei.type == "file"){
				//var _i = _ei.value.lastIndexOf("\\");
				_v = _ei.value,
						_contentType = _v && _v.match(/^(.*)(\.)(.{1,8})$/)[3];

				if(!_v || types.search(_contentType) != -1){//如果文件上传为空或者类型为限制类型则返回false
					return false;
				}
			}
		}
		return true;
	}

	clearFile = function(_eForm){//清空input为file的ui
		var _elements = _eForm.elements,
				_elementsLen = _elements.length,
				_ei = null,
				i = 0;
		for (; i < _elementsLen ; i++){
			_ei = _elements[i];
			(_ei.type == "file") && ((isIE() && (_ei.outerHTML = _ei.outerHTML)) || (_ei.value = ""));//如果为IE，利用其特性清空file文本数据，否则直接将value设置为空值
		}
	}

	fileUpload = function(){//上传文件的相关业务
		var _fileUpload = document.getElementById("fileUpload"),
				_addFileUpload = document.getElementById("addFileUpload"),
				_clearFileUpload = document.getElementById("clearFileUpload"),
				_filedemo1 = document.getElementById("filedemo1"),
				_fileUploadSub = document.getElementById("fileUploadSub");
		_fileUploadSub.onclick =function(){
			alert("测试获取文件大小：" + getFileSize(_filedemo1));//获取上传文件的大小
			if(!fileType(_fileUpload, "text")){//限制上传文件的格式 ---参数（上传文件的表单对象， 被限制的格式）
				return;
			}
		}

		_clearFileUpload.onclick =function(){//清除上传文件的内容
			clearFile(_fileUpload);
		}

		_addFileUpload.onclick =function(){//动态多文件上传，添加上传文件元素
			uploadCount++;
			var  _input=document.createElement("input"),
					_pE=document.createElement("p");
			_input.name="filedemo"+uploadCount;
			_input.id="filedemo"+uploadCount;
			_input.type="file";
			_pE.appendChild(_input);
			_fileUpload.insertBefore(_pE,document.getElementById("addFileUpload"));
		}
	}
	fileUpload();
};