js控制图片上传
<script language=javascript>//建立一个图像对象var ImgObj = new Image();//全部图片格式类型 var AllImgExt = ".jpg|.jpeg|.gif|.bmp|.png|"//全局变量 图片相关属性 var FileObj, ImgFileSize, ImgWidth, ImgHeight, FileExt, ErrMsg, FileMsg, HasCheked, IsImg//以下为限制变量 //允许上传的文件类型 ?为无限制 每个扩展名后边要加一个"|" 小写字母表示var AllowExt = ".jpg|.gif|.doc|.txt|.png|"//var AllowExt=0 var AllowImgFileSize = 1024; //允许上传图片文件的大小 0为无限制 单位：KB var AllowImgWidth = 2000; //允许上传的图片的宽度 ?为无限制 单位：px(像素) var AllowImgHeight = 2000; //允许上传的图片的高度 ?为无限制 单位：px(像素) HasChecked = false;function CheckProperty(obj) //检测图像属性 {FileObj = obj;if (ErrMsg != "") //检测是否为正确的图像文件 返回出错信息并重置 {ShowMsg(ErrMsg, false);return false; //返回 }if (ImgObj.readyState != "complete") //如果图像是未加载完成进行循环检测 {setTimeout("CheckProperty(FileObj)", 500);return false;}//取得图片文件的大小ImgFileSize = Math.round(ImgObj.fileSize / 1024 * 100) / 100;ImgWidth = ImgObj.width //取得图片的宽度ImgHeight = ImgObj.height; //取得图片的高度document.getElementById('picWidth').value = ImgWidth;document.getElementById('picHeight').value = ImgHeight;document.getElementById('picSize').value = ImgFileSize;document.getElementById('picType').value = FileExt;FileMsg = "\n图片大小:" + ImgWidth + "*" + ImgHeight + "px";FileMsg = FileMsg + " 图片文件大小:" + ImgFileSize + "Kb";FileMsg = FileMsg + " 图片文件扩展名:" + FileExt;if (AllowImgWidth != 0 && AllowImgWidth < ImgWidth)ErrMsg = ErrMsg + "\n图片宽度超过限制。请上传宽度小于" + AllowImgWidth+ "px的文件，当前图片宽度为" + ImgWidth + "px";if (AllowImgHeight != 0 && AllowImgHeight < ImgHeight)ErrMsg = ErrMsg + "\n图片高度超过限制。请上传高度小于" + AllowImgHeight+ "px的文件，当前图片高度为" + ImgHeight + "px";if (AllowImgFileSize != 0 && AllowImgFileSize < ImgFileSize)ErrMsg = ErrMsg + "\n图片文件大小超过限制。请上传小于" + AllowImgFileSize+ "KB的文件，当前文件大小为" + ImgFileSize + "KB";if (ErrMsg != "")ShowMsg(ErrMsg, false);elseShowMsg(FileMsg, true);}ImgObj.onerror = function() {ErrMsg = '\n图片格式不正确或者图片已损坏!'}//显示提示信息 tf=true 显示文件信息 tf=false 显示错误信息 msg-信息内容function ShowMsg(msg, tf) {msg = msg.replace("\n", "<li>");msg = msg.replace(/\n/gi, "<li>");if (!tf) {document.all.UploadButton.disabled = true;FileObj.outerHTML = FileObj.outerHTML;MsgList.innerHTML = msg;HasChecked = false;} else {document.all.UploadButton.disabled = false;if (IsImg)PreviewImg.innerHTML = "<img src='"+ImgObj.src+"' >"elsePreviewImg.innerHTML = "非图片文件";MsgList.innerHTML = msg;HasChecked = true;}}function CheckExt(obj) {ErrMsg = "";FileMsg = "";FileObj = obj;IsImg = false;HasChecked = false;document.getElementById('PreviewImg').innerHTML = "预览区";if (obj.value == "")return false;document.getElementById('MsgList').innerHTML = "文件信息处理中...";document.all.UploadButton.disabled = true;FileExt = obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase();//判断文件类型是否允许上传if (AllowExt != 0 && AllowExt.indexOf(FileExt + "|") == -1) {ErrMsg = "\n该文件类型不允许上传。请上传 " + AllowExt + " 类型的文件，当前文件类型为"+ FileExt;ShowMsg(ErrMsg, false);return false;}if (AllImgExt.indexOf(FileExt + "|") != -1) //如果图片文件，则进行图片信息处理 {IsImg = true;ImgObj.src = obj.value;CheckProperty(obj);return false;} else {FileMsg = "\n文件扩展名:" + FileExt;ShowMsg(FileMsg, true);}}function SwitchUpType(tf) {if (tf)str = '<input type="file" name="file1" onchange="CheckExt(this)" style="width:180px;">'elsestr = '<input type="text" name="file1" onblur="CheckExt(this)" style="width:180px;">'document.all.file1.outerHTML = str;document.all.UploadButton.disabled = true;MsgList.innerHTML = "";}</script>