js判断上传文件类型与文件大小等信息

UpLoadFileCheck = function () {
    this.AllowExt = ".jpg,.gif,.png,.jpeg"; //允许上传的文件类型 0为无限制 每个扩展名后边要加一个"," 小写字母表示
    this.AllowImgFileSize = 1; //允许上传文件的大小 0为无限制 单位：KB
    this.AllowImgWidth = 10; //允许上传的图片的宽度 0为无限制　单位：px(像素)
    this.AllowImgHeight = 10; //允许上传的图片的高度 0为无限制　单位：px(像素)
    this.ImgObj = new Image();
    this.ImgFileSize = 0;
    this.ImgWidth = 0;
    this.ImgHeight = 0;
    this.FileExt = "";
    this.ErrMsg = "";
    this.IsImg = false; //全局变量
}

UpLoadFileCheck.prototype.CheckExt = function (obj) {
    this.ErrMsg = "";
    this.ImgObj.src = obj.value;
    //this.Haschecked=false; 
    if (obj.value == "") {
this.ErrMsg = "n请选择一个文件";
    }
    else {
this.FileExt = obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase();
if (this.AllowExt != 0 && this.AllowExt.indexOf(this.FileExt) == -1)//判断文件类型是否允许上传
{
    this.ErrMsg = "n该文件类型不允许上传。请上传 " + this.AllowExt + " 类型的文件，当前文件类型为" + this.FileExt;
}
    }
    if (this.ErrMsg != "") {
this.ShowMsg(this.ErrMsg, false);
return false;
    }
    else
return this.CheckProperty(obj);
}

UpLoadFileCheck.prototype.CheckProperty = function (obj) {
    if (this.ImgObj.readyState != "complete")//
    {
sleep(1000); //一秒使用图能完全加载   
    }

    if (this.IsImg == true) {
this.ImgWidth = this.ImgObj.width; //取得图片的宽度
this.ImgHeight = this.ImgObj.height; //取得图片的高度
if (this.AllowImgWidth != 0 && this.AllowImgWidth < this.ImgWidth)
    this.ErrMsg = this.ErrMsg + "n图片宽度超过限制。请上传宽度小于" + this.AllowImgWidth + "px的文件，当前图片宽度为" + this.ImgWidth + "px";

if (this.AllowImgHeight != 0 && this.AllowImgHeight < this.ImgHeight)
    this.ErrMsg = this.ErrMsg + "n图片高度超过限制。请上传高度小于" + this.AllowImgHeight + "px的文件，当前图片高度为" + this.ImgHeight + "px";
    }

    this.ImgFileSize = Math.round(this.ImgObj.fileSize / 1024 * 100) / 100; //取得图片文件的大小 
    if (this.AllowImgFileSize != 0 && this.AllowImgFileSize < this.ImgFileSize)
this.ErrMsg = this.ErrMsg + "n文件大小超过限制。请上传小于" + this.AllowImgFileSize + "KB的文件，当前文件大小为" + this.ImgFileSize + "KB";

    if (this.ErrMsg != "") {
this.ShowMsg(this.ErrMsg, false);
return false;
    }
    else
return true;
}

UpLoadFileCheck.prototype.ShowMsg = function (msg, tf)//显示提示信息 tf=false 显示错误信息 msg-信息内容
{
    /*msg=msg.replace("n","<li>");
    msg=msg.replace(/n/gi,"<li>");
    */
    alert(msg);
}
function sleep(num) {
    var tempDate = new Date();
    var tempStr = "";
    var theXmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    while ((new Date() - tempDate) < num) {
tempStr += "n" + (new Date() - tempDate);
try {
    theXmlHttp.open("get", "about:blank?JK=" + Math.random(), false);
    theXmlHttp.send();
}
catch (e) { ; }
    }
    //containerDiv.innerText=tempStr; 
    return;
}

function c(obj) {
    var d = new UpLoadFileCheck();
    d.IsImg = true;
    d.AllowImgFileSize = 100;
    d.CheckExt(obj)
}
//调用 <input name="" type="file" onchange="c(this)" />
    </script>
 
<script type="text/javascript">
function ajaxFunction()
{
  var xmlHttp;
  try
{
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
}
  catch (e)
{
    // Internet Explorer
    try
    {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e)
    {
      try
      {
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (e)
      {
alert("您的浏览器不支持AJAX!");
return false;
      }
    }
}
}