请问怎样在HTML的编程环境下，能直接读取到JPG和GIF图片文件的高度和宽度（用pixel表示）？

<HTML><HEAD>
<SCRIPT>function getImageDimension (imgURL, loadHandler) {
  var img = new Image();  
img.onload = loadHandler;  
if (document.layers && location.protocol.toLowerCase() != 'file:' && navigator.javaEnabled())
    netscape.security.PrivilegeManager.enablePrivilege(      'UniversalFileRead'
    );  img.src = imgURL;}
function getFileSize (fileName) {
  if (document.layers) {    
if (navigator.javaEnabled()) {
      var file = new java.io.File(fileName);
      if (location.protocol.toLowerCase() != 'file:')
        netscape.security.PrivilegeManager.enablePrivilege(
        'UniversalFileRead'        );      
return file.length();    }
    else return -1;  }  
else if (document.all) {
    window.oldOnError = window.onerror;    
window.onerror = function (err) {
      if (err.indexOf('utomation') != -1) {
        alert('file access not possible');        
return true;      
}     
 else 
       
 return false;    };
    var fso = new ActiveXObject('Scripting.FileSystemObject');
    var file = fso.GetFile(fileName);    
window.onerror = window.oldOnError;
    return file.Size;  }}
function showImageDimensions () {
  alert(this.width + 'x' + this.height);}
</SCRIPT>
<SCRIPT>
function checkImageDimensions (fileName) {  
var imgURL = 'file:///' + fileName;
  getImageDimension(imgURL, showImageDimensions);}
</SCRIPT>
</HEAD
><BODY>
<FORM NAME="formName"><INPUT TYPE="file" NAME="fileName"><BR>
<INPUT TYPE="button" VALUE="check file size"
       ONCLICK="alert(getFileSize(this.form.fileName.value))"><BR>
<INPUT TYPE="button" VALUE="check image dimensions"
       ONCLICK="checkImageDimensions(this.form.fileName.value)"></FORM></BODY>
</HTML>

解决方案 »

  1.   

    <HTML><HEAD><SCRIPT>  function getImageDimension(imgURL,loadHandler) 
        {
         var img = new Image();  
         img.onload = loadHandler;  
         if (document.layers && location.protocol.toLowerCase() != 'file:' && navigator.javaEnabled())
            {
             netscape.security.PrivilegeManager.enablePrivilege('UniversalFileRead');
            }
         img.src = imgURL;
        }  function getFileSize(fileName)
        {
         if (document.layers) 
            {    
             if (navigator.javaEnabled())
                {
                 var file = new java.io.File(fileName);
                 if (location.protocol.toLowerCase() != 'file:')
                    {
                     netscape.security.PrivilegeManager.enablePrivilege('UniversalFileRead');
                    }      
                 return file.length();
                }
             else
                {
                 return -1;
                }
            }  
         else if (document.all)
            {
             window.oldOnError = window.onerror;    
             window.onerror = function (err)
               {
                if (err.indexOf('utomation') != -1)
                   {
                    alert('file access not possible');        
                    return true;      
                   }     
                else
                   {  
                    return false;
                   }
               }
             var fso = new ActiveXObject('Scripting.FileSystemObject');
             var file = fso.GetFile(fileName);    
             window.onerror = window.oldOnError;
             return file.Size;
            }
        }  function showImageDimensions()
        {
         alert(this.width + 'x' + this.height);
        }  function checkImageDimensions (fileName)
        {  
         var imgURL = 'file:///' + fileName;
         getImageDimension(imgURL,showImageDimensions);
        }
    </SCRIPT></HEAD><BODY>
    <FORM NAME="formName"><INPUT TYPE="file" NAME="fileName"><BR>
    <INPUT TYPE="button" VALUE="check file size" ONCLICK="alert(getFileSize(this.form.fileName.value))"><BR>
    <INPUT TYPE="button" VALUE="check image dimensions" ONCLICK="checkImageDimensions(this.form.fileName.value)">
    </FORM>
    </BODY></HTML>