LanceZhang’s Blog

Dear friends, Welcome to my blog.

Preview and check Image info before upload

That will only work in IE:

<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd&#8221;>
<html xmlns=”http://www.w3.org/1999/xhtml&#8221;>
<head>
    <title>validate before upload by Lance Zhang</title>
</head>
<body style=”font-family:Calibri”>
    <form name=”Myform”>
    <p>
        <font color=”red” size=”6″>File type :gif,jpg,jpeg,png,bmp</font></p>
    <p>
        File Size limit:
        <input type=”text” size=”4″ value=”100″ name=”fileSizeLimit” id=”fileSizeLimit” />
        K</p>
    <p>
        Image Height Limit: <input type=”text” size=”4″ value=”100″ name=”heightLimit” id=”heightLimit” />
    </p>
    <p>
        Image Width Limit: <input type=”text” size=”4″ value=”100″ name=”widthLimit” id=”widthLimit” />
    </p>
    <p>
        <input type=”file” name=”photo” onchange=”changeSrc(this)” />
        Image Preview<img src=”about:blank” id=”fileChecker” name=”fileChecker” alt=”test” />
    </p>
    <p>
        <input type=”submit” value=”submit”>
    </p>
    </form>

    <script type=”text/javascript”>
      function   CheckFileSize()   
      { 
        var limit = document.getElementById(“fileSizeLimit“).value * 1024;
        var width = document.getElementById(“widthLimit“).value ;
        var height = document.getElementById(“heightLimit“).value;
     
        if (oFileChecker.fileSize > limit)
        {
            alert(“FileSize :“+oFileChecker.fileSize+“byte–too large!“);
        }
        else
        {
            alert(“FileSize :“+oFileChecker.fileSize+“byte–ok“);
        }
     
        if(  oFileChecker.height> height)
        {
            alert(“ImageHeight :“+oFileChecker.height+“–too height!“);
        }
        else
        {
            alert(“ImageHeight :“+oFileChecker.height+“–ok“);
        }
        if(oFileChecker.width> width)
        {
            alert(“ImageWidth :“+oFileChecker.width+“–too width!“);
        }
        else
        {
            alert(“ImageWidth :“+oFileChecker.width+“–ok“);
        }
            return false;   
      } 
      
      var right_type=new Array(“.gif“,“.jpg“,“.jpeg“,“.png“,“.bmp“);

      var oFileChecker = document.getElementById(“fileChecker“);

     function changeSrc(filePicker)
     { 
        if(!checkImgType(filePicker.value))
        {
            alert(“the file type is not correct“);
            return;
        }
        oFileChecker.src = filePicker.value;
     }

    oFileChecker.onreadystatechange = function ()
    { 
        if (oFileChecker.readyState == “complete“)
        {
            CheckFileSize();
        }
    }

    function checkImgType(fileURL)
    {
        var right_typeLen=right_type.length;
        var imgUrl=fileURL.toLowerCase();
        var postfixLen=imgUrl.length;
        var len4=imgUrl.substring(postfixLen–4,postfixLen);
        var len5=imgUrl.substring(postfixLen–5,postfixLen);
        for (i=0;i<right_typeLen;i++)
        {
            if((len4==right_type[i])||(len5==right_type[i]))
            {
                return true;
            }
        }
    }

</script>

</body>
</html>

February 16, 2009 Posted by | Code and Solution, JavaScript | | 7 Comments