var isIE = /msie/i.test(navigator.userAgent) && !window.opera;

			function fileChange(target, id) {
				var fileSize = 0;
				var filetypes = [".jpg", ".png", ".bmp", "gif", "jpeg"];
				var filepath = target.value;
				var filemaxsize = 1024 * 2; //2M 
				if (filepath) {
					var isnext = false;
					var fileend = filepath.substring(filepath.indexOf("."));
					if (filetypes && filetypes.length > 0) {
						for (var i = 0; i < filetypes.length; i++) {
							if (filetypes[i] == fileend) {
								isnext = true;
								break;
							}
						}
					}
					if (!isnext) {
						alert("不接受此文件类型！");
						target.value = "";
						return false;
					}
				} else {
					return false;
				}
				if (isIE && !target.files) {
					var filePath = target.value;
					var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
					if (!fileSystem.FileExists(filePath)) {
						alert("附件不存在，请重新输入！");
						return false;
					}
					var file = fileSystem.GetFile(filePath);
					fileSize = file.Size;
				} else {
					fileSize = target.files[0].size;
				}
				var size = fileSize / 1024;
				if (size > filemaxsize) {
					alert("附件大小不能大于" + filemaxsize / 1024 + "M！");
					target.value = "";
					return false;
				}
				if (size <= 0) {
					alert("附件大小不能为0M！");
					target.value = "";
					return false;
				}
				var MAXWIDTH = 260;
				var MAXHEIGHT = 260;
				var div = document.getElementById('preview');
				if (target.files && target.files[0]) {
					div.innerHTML = '<img id=imghead>';
					var img = document.getElementById('imghead');
					img.onload = function() {
						var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
						img.width = rect.width;
						img.height = rect.height;
						img.style.marginTop = rect.top + 'px';
					}
					var reader = new FileReader();
					reader.onload = function(evt) {
						img.src = evt.target.result;
					}
					reader.readAsDataURL(target.files[0]);
				} else //兼容IE
				{
					var sFilter = 'filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
					target.select();
					var src = document.selection.createRange().text;
					div.innerHTML = '<img id=imghead>';
					var img = document.getElementById('imghead');
					img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
					var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
					status = ('rect:' + rect.top + ',' + rect.left + ',' + rect.width + ',' + rect.height);
					div.innerHTML = "<div id=divhead style='width:" + rect.width + "px;height:" + rect.height + "px;margin-top:" + rect.top + "px;" + sFilter + src + "\"'></div>";
				}
			}

			function clacImgZoomParam(maxWidth, maxHeight, width, height) {
				var param = {
					top: 0,
					left: 0,
					width: 100,
					height: 100
				};
				return param;
			}