JS judge file format and size of a simple example (must SEE) _javascript skills

Examples are as follows:

Determines the photo size
function getphotosize (obj) {
  photoext=obj.value.substr (obj.value.lastIndexOf (".")). toLowerCase ()//Get file suffix name
  if (photoext!= '. jpg ') {
    alert ("Please upload a photo with suffix name jpg!");
    return false;
  }
  var fileSize = 0;
  var Isie =/msie/i.test (navigator.useragent) &&!window.opera;      
  if (Isie &&!obj.files) {     
     var filePath = obj.value;      
     var filesystem = new ActiveXObject ("Scripting.FileSystemObject");  
     var file = Filesystem.getfile (FilePath);        
     fileSize = file. Size;     
  } else { 
     fileSize = obj.files[0].size;   
  } 
  Filesize=math.round (filesize/1024*100)/100; The Unit is KB
  if (filesize>=10) {
    alert ("Photo maximum size is 10KB, please upload it again!");
    return false;
  }
}

JSP page:

<input type= "File" id= "Imgfile name=" upload "style=" width:150px; "onchange=" getphotosize (this)/>

The above is small series for everyone to bring the JS judge file format and size of a simple example (must see) all the content, I hope that we support cloud Habitat Community ~