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Javascript causes php session register to fail

Posted on 2007-04-01
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Last Modified: 2008-01-09
I have a php script that lets select users upload files for distribution.  The script works fine and maintains session variables across multiple pages, such as a verification page for the upload, an edit page, the verification page again, and finally an action page.

The session variables were added to the session by using the following as required for all the variables:

$_SESSION['variable_name'] = $_POST['field_data'];

where variable_name is replaced by the session variable name and field_data is the name of the field coming from the form.

Sometimes the files could take a minute or two to upload, so I decided to add the CastleBusyBox javascript to the page so that the user sees an animated gif while the files are uploading.

This worked fine, except that the php session variables stopped getting registered.  Actually, I think they were registered but the values were not passed to the session, because I see the variable name but it has now value, like: email_subject|N

The CastleBusyBox.js (which is added at the bottom of this post) requires a few lines be added to the web page.

onbeforeunload="busyBox.Show();" is added to the 'body' tag so it now looks like <body onbeforeunload="busyBox.Show();">

<iframe id="BusyBoxIFrame" name="BusyBoxIFrame" frameBorder="0" scrolling="no" ondrop="return false;">
</iframe>
<script language="javascript">
// Instantiate our BusyBox object
var busyBox = new BusyBox("BusyBoxIFrame", "busyBox", 4, "/artwork/gears_ani_", ".gif", 125, 147, 207);
</script>

is added just before the </form> tag.

Interestingly, if I remove only the var busyBox = new BusyBox("BusyBoxIFrame", "busyBox", 4, "/artwork/gears_ani_", ".gif", 125, 147, 207); line the php session data is written properly again.

Any ideas?

Thanks.

Alan Pollenz

----------------------------------------------------------------------------------------------

CastleBusyBox.js code (placed just below the <body> tag:

<script language="javascript">

// ---------------------------
// Legal
// ---------------------------
// CastleBusyBox Control
// Castle Rock Software, LLC
// by Mark Wagner
// http://www.crsw.com
//
// Version: 1.2
//
// Copyright 2004, 2005 Castle Rock Software, LLC
// No warranty express or implied.

// ---------------------------
// General Notes
// ---------------------------
// The BusyBox javascript has been written so the BusyBox javascript
// control can be used with or without the Castle.BusyBox .NET control.

// ---------------------------
// Constructor
// ---------------------------
// BusyBox class constructor
// Arguments:
//   id - id of the IFrame tag to use.
//   varName - name of the variable this instance of the busy box is assigned to.
//   imageCount - number of image in the animation sequence.
//   imageNamePrefix - name prefix for each image.
//   imageNameSuffix - name suffix for each image.
//   imageDelay - number of milliseconds to display each image.
//   width - defines the width of the busy box (required for Netscape and Firefox)
//   height - defines the height of the busy box (required for Netscape and Firefox)
//   url - (optional) url to the page containing the custom busy box layout.
//
//   This example uses the default busy box layout defined internally (in the javascript).
//   var busyBox = new BusyBox("BusyBox1", "busyBox", 4, "gears_ani_", ".gif", 125, 147, 206)
//
//   This example uses a custom busy box layout defined in the BusyBox.htm file.
//   var busyBox = new BusyBox("BusyBox1", "busyBox", 4, "gears_ani_", ".gif", 125, 147, 206, "BusyBox.htm")
//

function BusyBox(id, varName, imageCount, imageNamePrefix, imageNameSuffix, imageDelay, width, height, url)
{
      // Initialize object
      this.id = id;
      this.ImageCount = imageCount;
      this.CurrentImageIndex = 0;
      this.ImageWidth = 0;
      this.ImageHeight = 0;
      this.ImageNamePrefix = imageNamePrefix;
      this.ImageNameSuffix = imageNameSuffix;
      this.ImageDelay = imageDelay;
      this.DivID = "BusyBoxDiv";
      this.ImgID = "BusyBoxImg";
      this.Enabled = true;
      this.Width = width;
      this.Height = height;
      
      // Retain the name of the instantiated object variable so that we can animate
      // using the setTimeout statement
      this.VarName = varName;
      
      // Allows us to stop the animation with clearTimeout(), should we ever want to
      this.timeout_id = null;
      
      // Cache (pre-load) images
      this.CacheImages();
      
      // Url to the page containing the busy box.
      this.BusyBoxUrl = url;
      
      // Get reference to the IFrame object
      this.IFrame = document.getElementById(this.id);
      
      // Hide the busy box
      this.Hide();
      
      if( this.BusyBoxUrl )
            // Load the busy box contents using a custom layout page.
            this.LoadUrl(this.BusyBoxUrl);
      else
            // Load the busy box contents using the internally defined layout.
            this.RenderContent();
      
      // If this browser does not support IFRAME tags then disable this control.  The
      // next version will implement the use of a DIV instead of the IFRAME tag;
      // even though there are a couple minor issues with using DIV tags.
      if( !frames[this.id] )
            this.Enabled = false;
}

// --------------------------------
// Instance Methods
// --------------------------------

// GetIFrameDocument:
// Returns a reference to the document object in the IFrame.
BusyBox.prototype.GetIFrameDocument = function()
{
      var doc;
      
      if( this.IFrame.contentDocument )
            // For NS6
            doc = this.IFrame.contentDocument;
      else if( this.IFrame.contentWindow )
            // For IE5.5 and IE6
            doc = this.IFrame.contentWindow.document;
      else if( this.IFrame.document )
            // For IE5
            doc = this.IFrame.document;
      else
// TODO: Confirm this should be the default
            doc = this.IFrame.document;
      
      return doc;
}

// LoadUrl:
// Changing the src attribute for an IFrame tag causes each new page to be
// added to the browsers history object.  This causes undesired results for
// the user when they click the back button.  Instead, we can use the
// document.location.replace() method to correctly load our busy box
// page into our IFrame.
//
// Arguments:
//            url - url to the busy box page.
BusyBox.prototype.LoadUrl = function(url)
{
      // Get a reference to the document object in the IFrame
      var IFrameDoc = this.GetIFrameDocument();
      
      // Load the url using the replace method.  This will prevent the browsers
      // history object from being updated with the new busybox url; thus allowing
      // the back button to function as desired for the user.
      IFrameDoc.location.replace(url);
}

// RenderContent:
// This method is used when the default busy box layout is used; not a custom
// layout.  This method is called when the url argument for the constructor is null.
BusyBox.prototype.RenderContent = function()
{
      // Get the IFrame document object
      var doc = this.GetIFrameDocument();
      
      var style = " style='BORDER: navy 3px solid; POSITION: absolute;' ";
      
      doc.open();
      doc.writeln("<body ondragstart='return false;' style='Margin: 0px; Background-Color: white'>");
      doc.writeln("   <div id='" + this.DivID + "' align=center " + style + ">");
      doc.writeln("      <img id='" + this.ImgID + "' src=''>");
      doc.writeln("      <br><h3>Processing</h3>");
      doc.writeln("   </div>");
      doc.writeln("</body>");
      doc.close();
}

// Resize:
// Resizes the busy box IFrame by setting its width and height attributes
// to the size of its contents.
BusyBox.prototype.Resize = function()
{
      // Resize the busy box IFrame.
      if( BusyBox.IsBrowserIE() )
      {
            // Set the width by looking at its contents
            var div = frames[this.id].document.getElementById(this.DivID);
            this.IFrame.style.width = div.offsetWidth;
            this.IFrame.style.height = div.offsetHeight;
      }
      else
      {
            // Set the width to the value specified.
            this.IFrame.style.width = this.Width;
            this.IFrame.style.height = this.Height;
      }
}

// Center:
// Centers the busy box IFrame on the page regardless of the browsers
// scroll position.  This ensures the busy box is presented to the user
// in a visible location in the window.
BusyBox.prototype.Center = function()
{
      if( !this.IFrame )
            return;
      
      // Center the BusyBox in the window regardless of the scroll positions
      var objLeft = (document.body.clientWidth - this.IFrame.offsetWidth) / 2;
      var objTop = (document.body.clientHeight - this.IFrame.offsetHeight) / 2;
      objLeft = objLeft + document.body.scrollLeft;
      objTop = objTop + document.body.scrollTop;
      
      // Position object
      this.IFrame.style.position = "absolute";
      this.IFrame.style.top = objTop;
      this.IFrame.style.left = objLeft;
}

// CacheImages:
// Pre-loads the images from the server and stores a reference to each
// image.  This allows the images to be presented to the user quickly
// for smooth image animation.
BusyBox.prototype.CacheImages = function()
{
      // Instantiate the array to store the image references
      this.Images = new Array(this.ImageCount);
      
      // Load all the images to cache into the aniframes array
      for(var i = 0; i < this.ImageCount; i++)
      {
            this.Images[i] = new Image();
            this.Images[i].src = this.ImageNamePrefix + i + this.ImageNameSuffix;
      }
}

// IsAnimating:
// Returns a boolean value representing the state of the animation.
BusyBox.prototype.IsAnimating = function()
{
      if( this.timeout_id == null)
            return false;
      else
            return true;
}

// IsVisible:
// Returns a boolean value representing the visibility state for the busy box.
BusyBox.prototype.IsVisible = function()
{
      var ifrm = document.getElementById(this.id);
      
      if( ifrm.style.visibility == "visible" && ifrm.style.width > 0 )
            return true;
      else
            return false;
}

// Animate:
// Performs the animation process.  This is accomplished by showing the "current"
// image in the animation sequence process; and then submitting a timed statement
// to execute in x number of milliseconds.
BusyBox.prototype.Animate = function()
{
      // Assign the current image sequence to display
      if( frames[this.id] )
            // browser supports frames
            frames[this.id].document.getElementById(this.ImgID).src = this.Images[this.CurrentImageIndex].src;
      else
            // browser does not support frames
            document.getElementById(this.ImgID).src = this.Images[this.CurrentImageIndex].src;
      
      // Auto re-center and re-size the busy box.  This will force the busy box to
      // always appear in the center of the window even if the user scrolls.
      this.Resize();
      this.Center();
      
      // Increment the current image index
      this.CurrentImageIndex = (this.CurrentImageIndex + 1)%this.ImageCount;
      
      // Display the next image in (imageDelay value) milliseconds (i.e. 125)
      this.timeout_id = setTimeout(this.VarName + ".Animate();", this.ImageDelay);
}

// StartAnimation:
// Starts the animation process.
BusyBox.prototype.StartAnimate = function()
{
      if( this.IsAnimating() )
            return;
      
      this.Animate();
}

// StopAnimation:
// Stops the animation process.
BusyBox.prototype.StopAnimate = function()
{
      clearTimeout(this.timeout_id);
      this.timeout_id = null;
}

// Hide:
// Hides the busy box making it invisible to the user.
BusyBox.prototype.Hide = function()
{      
      this.StopAnimate();
      
      // Hide the busy box.
      this.IFrame.style.visibility = "hidden";
      this.IFrame.style.width = 0;
      this.IFrame.style.height = 0;
}

// Show:
// This function displays the busy box to the user.  This function centers the
// busy dialog box, makes it visible, and starts the animation.  This function
// will typically be called by the body event.
//
// Example:
//            <body onbeforeunload="busyBox.Show();" >
BusyBox.prototype.Show = function()
{
      if( !this.Enabled )
            return;

      if( this.IsAnimating() || this.IsVisible() )
            return;      
      
      this.Resize();
      this.Center();
      
      // Set the busy box to be visible and make sure it is on top of all other controls.      
      this.IFrame.style.visibility = "visible";
      this.IFrame.style.zIndex = "999999";
      
      // Start the animation
      this.StartAnimate();
}

// --------------------------------
// Class Methods
// --------------------------------

// IsBrowserIE:
// Returns true if the executing browser it a Microsoft Internet Explorer browser.
BusyBox.IsBrowserIE = function()
{
      try
      { return (window.navigator.userAgent.indexOf("MSIE ") > 0); }
      catch(x)
      { return false; }
}

// IsBrowserNS:
// Returns true if the executing browser it a Netscape browser.
BusyBox.IsBrowserNS = function()
{
      try
      { return (window.navigator.userAgent.indexOf("Netscape") > 0); }
      catch(x)
      { return false; }
}

// IsBrowserFirefox:
// Returns true if the executing browser it a Firefox browser.
BusyBox.IsBrowserFirefox = function()
{
      try
      { return (window.navigator.userAgent.indexOf("Firefox") > 0); }
      catch(x)
      { return false; }
}
</script>
0
Comment
Question by:alanpollenz
  • 2
3 Comments
 
LVL 19

Accepted Solution

by:
BrianGEFF719 earned 500 total points
ID: 18833241
Dont put it in the form, put it before your first form tag.
0
 

Author Comment

by:alanpollenz
ID: 18833347
Brian,

When I moved:

<script language="javascript">
// Instantiate our BusyBox object
var busyBox = new BusyBox("BusyBoxIFrame", "busyBox", 4, "/artwork/gears_ani_", ".gif", 125, 147, 207);
</script>

outside the form tag, the php sessions work properly again but the animated gif does not show up while files are being uploaded.

Alan
0
 

Author Comment

by:alanpollenz
ID: 18873256
Used a different javascript to solve problem.
0

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