js判断上传文件的类型和大小示例代码

复制代码 代码如下:

  //检测文件大小和类型

  function fileChange(target){

  //检测上传文件的类型

  if(!(/(?:jpg|gif|png|jpeg)$/i.test(target.value))) {

  alert("只允许上传jpg|gif|png|jpeg格式的图片");

  if(window.ActiveXObject) {//for IE

  target.select();//select the file ,and clear selection

  document.selection.clear();

  } else if(window.opera) {//for opera

  target.type="text";target.type="file";

  } else target.value="";//for FF,Chrome,Safari

  return;

  } else {

  return; //alert("ok");//or you can do nothing here.

  }

  //检测上传文件的大小

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

  var fileSize = 0;

  if (isIE && !target.files){

  var filePath = target.value;

  var fileSystem = new ActiveXObject("Scripting.FileSystemObject");

  var file = fileSystem.GetFile (filePath);

  fileSize = file.Size;

  } else {

  fileSize = target.files[0].size;

  }

  var size = fileSize / 1024;

  if(size>(500)){

  alert("文件大小不能超过500KB");

  if(window.ActiveXObject) {//for IE

  target.select();//select the file ,and clear selection

  document.selection.clear();

  } else if(window.opera) {//for opera

  target.type="text";target.type="file";

  } else {

  target.value="";//for FF,Chrome,Safari

  }

  return;

  }else{

  return;

  }

  }