This support FAQ (Frequently Asked Questions) is intended to assist you in providing all the relevant information so that we may provide you with a timely and accurate resolution to your problem or question.  The topics are of a general support nature and applicable to any Joomla problem that may be encountered and provide guidance in obtaining additional information to enable a speedy resolution.

 

Blank Page Shown

Sometimes, due to a PHP error, scripts stop working without displaying an error, leading you to a blank page.

In that case, to find out what is the real cause, you should do the following: Check server error logs (not access logs) if you have access to them.

Go to your Joomla Administration panel, Site --> Global Configuration --> System Tab and turn on Site Debugging, then try reloading page, and check page source (HTML source). Don't forget to turn site debug off again after you have finished.

If the blank page is outside of a component (no "option=com_xxxxxx" in the URL), e.g. in Joomla during installation, add following to the index.php in the front end or the back end where it gives you a blank page, just after the first " ini_set( 'display_errors', true ); error_reporting( E_ALL );

Check your web server error log for errors generated by your website. You might be able to locate the culprit by identifying the logged error. One common cause is lack of memory.

Controlling Joomla cache

In order to improve site perfomance Joomla implements cache to present the fastest user experience possible to the visitor. As someone clicks through the site, Joomla makes snapshots of where they have been and saves them to a temporary directory. If the person wants to return to a previous location, the server grabs the temporarily saved page, which should be faster than going back to the data base and generating an entire new page.

How to control Cache in joomla?

Go to menu Site, Global Configuration and choose server tab.

Set the cache setting to the desired value.

Be aware that some templates also provide some form of cache, so it you are experiencing a cache problem it might not be teh Joomla system cache that is at fault.

Controlling Strict Standards reporting

If you get following warning(s) on your site:

Strict Standards: Non-static method ... on line XX

and you are running Joomla! 2.5, go to your Joomla! Global Configuration - Server and set the parameter Error Reporting to None.

 

Changing php error reporting on server side:

You can disable Strict Standards on your server too, in php settings.

Go to your php.ini (or ask your webhosting provider) and disable Strict Standards on your server.

The attribute is called: error_reporting

Example:

From:

error_reporting = E_ALL | E_STRICT

To:

error_reporting = E_ALL | E_DEPRECATED

, (of course Error Reporting parameter in Joomla! Global Configuration can overwrite this settings)

A lot of Joomla! extensions were written for PHP4 and PHP 5. Mostly PHP4 code caused these warnings. It is not possible to change all the code to new rules set in PHP 5.3, PHP 5.4 or newest immediately) - e.g. if some extension has over 50.000 lines of code.ary directory.

HTTP 500 Internal Server Errors

HTTP status messages are defined by the World Wide Web Consortium to provide "human-readable diagnostic information". These status messages are generated by the webserver that hosts a website.

The error code HTTP 500 Internal Server Error is a general-purpose error message this indicates a general error in a web application.

HTTP 500 Internal Server Errors can arise from one or more of the following causes (this is not a complete list):

  • Unexpected and fatal errors in both Joomla core and its extensions
  • Bugs in Joomla extensions Insufficient server resources (usually PHP memory limit is too low)
  • Badly-constructed web server configuration files (e.g. httpd.conf and .htaccess)
  • Bugs in web server software (Apache, PHP)

Because HTTP 500 Internal Server Errors arise from so many different sources, it is often necessary to enable Joomla debug mode. This is achieved with the following settings (J! 2.5 and J! 3.1):

  • Global Configuration » System » Debug Settings » Debug System = Yes
  • Global Configuration » Server » Server Settings » Error Reporting = Maximum

These changes may provide additional information. In addition, there will be other details recorded in the server logs (which may or may not be available depending upon your host provider) that can be looked at to see what else is happening.

Controlling Site Error reporting

Warning For security reasons it is not advisable to have Error Reporting turned on upon a live site, so care should be exercised with these setting in these situations.

To control Site error reporting go to your Joomla Administration panel, Site --> Global Configuration --> System Tab and turn on Site Debugging, then try reloading page, and check page source (HTML source). Don't forget to turn site debug off again after you have finished.

It is also possible to set PHP error reporting on within the php.ini file (if you have access to this file). Set the following lines:

error_reporting  =  E_ALL
display_errors = On

If you have no access to php.ini file but you can modify .htaccess file on your server (in the root of your public_hml folder upon your Joomla! site), try to add the following code there (on some servers this option is disabled, so you will have to ask your webhosting operator):

# Displaying PHP errors
php_flag display_errors on
php_value error_reporting 6143

If you cannot access the .htaccess file or your modifications in this file have no effects, try to ask your webhosting provider for enabling error reporting or try to see your error log file (which should be located outside your public_html folder), which can give you important information too.

After you will get the information about the problem and you resolve your problem, you should disable php error reporting again, so no error will be displayed for the public (because of security reasons).
 

PHP Errors

Typically PHP errors may be shown by a message similar to:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in ...

This error mostly means, there is some error in your database. This error can be easily recognized by enabling debug mode in Joomla! configuration. Go to your Joomla! administration - Site - Global Configuration - System. Set Debug System to Yes.

Now reload the page where the error occurs. You should get detailed information from your database. Mostly you get error output similar to this: Unknown column 'a.column' in 'on clause' SQL=SELECT ...

In this case a database column is missing for the component. So the component needs to be modfied and/or reinstalled or the column (table) needs to be added manually into the database.

JavaScript Errors

If some of Javascript feature does not work, it may well be that there is a Javascript error. Javascript errors can be displayed by Javascript console or by specific browser extensions. E.g. in Firefox you can use Firebug to see if on your site, some Javascript error is rendered.

To get info about Javascript error:

  • Enable Javascript console in your browser
  • Or install and enable the specific extension for your browser similar to that of Firefox Firebug.

The Joomla! CMS is quite complex and a very extensible system, consequently on a page, many different extensions can be loaded together. E.g. component Javascript + system plugin Javascript + module Javascript + template Javascrpt can be loaded at once. Loading many different Javascript libraries at once can produce Javascript error. To get info about this error, just use methods mentioned above. To recognize which parts of the site (component, plugin, module, template) are in conflict, just try to disable all of them and start to enable them step by step. Switching to standard template to test the errors is the first step.

Memory Size Errors

The error message generally looks similar to:

Allowed memory size of ... bytes exhausted ...

This error is a memory error on server. This error has not to our knowledeg been seen with our extensions, but since it such a common error it is included here for completeness.

It usually indicates that some library which is a part of PHP on your server, does not have enough memory to complete its task. It is often associated with the creation of thumbnails from large image files.

Possible solutions:

  1. Increase PHP memory on your server (if you are able to do)
  2. If it is image related, try using smaller images.

Provide useful information

Have you read the documentation before posting? Often questions and problems are answered in the documentation.

Have you searched the support forum to see if others have reported the problem?

  Please include as much detail in any test or bug reports as possible.

First of all, check if you are running the latest available version of Joomla! and the product.  Especially make it clear which extension you are experiencing problems with.

We need the following at least:

  • PHP version (e.g. 5.3.14). Note: Support for PHP4 is not provided.
  • Joomla! version
  • Product and product version version
  • Web Server software (Apache or IIS with version number if possible)
  • Server Operating system (e.g. Linux, Windows, Solaris, ...)
  • Database version
  • Web browser and version (e.g. Firefox 16, IE 9 , Chrome, ...)
  • memory_limit from your phpinfo
  • Host: (optional, but it may help us to help you)

Please enable error reporting and include any error messages in your posting. You do this via the Joomla Configuration - set "error reporting" to "maximum" on the Server tab.

Finally, please describe the steps required to recreate the problem and also please enable error reporting and provide any error messages generated.

end faq

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