How to get previous page url in PHP

$realname = basename($_SERVER['HTTP_REFERER'], ".php");

Multiple submit button in a single form in PHP

<form method="post">
<input type="submit" name="save" value="Submit 1">
<input type="submit" name="cancel" value="Submit 2">
</form>


<?php
if (isset($_POST['save'])) {
  // code
}
else if (isset($_POST['cancel'])) {
  // code
}
?>

Installing the Java Plugin for Firefox on CentOS

The OpenJDK bundled with CentOS is missing a java plugin for Firefox. A simple method of getting Java to run inside the webbrowser and to run java applications is to install icedtea-web

Open a terminal and type the below command

yum install icedtea-web

Then restart your browser
Click Tools- >Add-ons
The Add-ons Manager tab will open.
In the Add-ons Manager tab, select Plugins
Click icedtea-web plugin to select it and click on the Enable button

The java verification applet (http://www.javatester.org/version.html) works fine.

Installing and configuring Java in cent OS

Most of the Linux operating systems comes with pre-installed OpenJDK package to run java-based applications and plugins.But in certain cases we need Sun/Oracle Java program to compile and run
particular development applications.

1. Download java from  
http://www.oracle.com/technetwork/java/javase/downloads/index.html

2. install java using rpm -uvh
   ## Install Java on 32-Bit OS ##
   # rpm -Uvh jdk-7u45-linux-i586.rpm
   # rpm -Uvh jdk-7u45-linux-i586.rpm

   ## Install Java on 64-Bit OS ##
   # rpm -Uvh jdk-7u45-linux-x64.rpm
   # rpm -Uvh jdk-7u45-linux-x64.rpm

3. check java installed
   # java -version

   output should be
   java version "1.7.0_45"

4. Setting up java environment variables
The easiest way to set an environment variable in CentOS is to use export as in

$> export JAVA_HOME=/usr/java/jdk.1.7.0_45

$> export PATH=$PATH:$JAVA_HOME

However, variables will disappear the moment you exit the shell. Obviously this is not helpful when setting environment variables that need to persist even when the system reboots.In such cases, you need to set the variables within the system wide profile. In CentOS , the folder /etc/profile.d/ is the recommended place to add  customizations to the system profile.

5. Create a new file called java.sh
vim /etc/profile.d/java.sh

6. Copy paste the below content in java.sh

export JRE_HOME=/usr/java/jdk.1.7.0_45/jre
export PATH=$PATH:$JRE_HOME/bin
export JAVA_HOME=/usr/java/jdk.1.7.0_45
export JAVA_PATH=$JAVA_HOME
export PATH=$PATH:$JAVA_HOME/bin

7.  If you want to load the environment variables within java.sh without having  to restart the machine, you can use the source command as in:
   $> source java.sh

Add horizontal scrollbar to html table

Inorder to add a horizontal scroll bar on html table automatically as the table grows, we need to wrap the table inside a div and add overflow:auto css property

For eg:

<div style="white-space:pre;overflow:auto;width:500px;padding:10px;"> <table style="width:900px;"> <tr> <td>text1</td> <td>text2</td> <td>text3</td> </tr> </table> </div>

Fatal error: Call to undefined function http_redirect() : Fixed

Issue: When I was trying to call the PHP http_redirect() function, below error came up:

Fatal error: Call to undefined function http_redirect() in location.

Add the below function in your php page
/**
 * redirect to a specific URL
 * @param $url
 */
     function redirect($url)
{
     if (!headers_sent())
     {  
          //If headers not sent yet... then do php redirect
          header('Location: '.$url); exit;
     }
     else
     {                  
          //If headers are sent... do javascript redirect...
          //if javascript disabled, do html redirect.
          echo '<script type="text/javascript">';
          echo 'window.location.href="'.$url.'";';
          echo '</script>';
          echo '<noscript>';
          echo '<meta http-equiv="refresh" content="0;url='.$url.'" />';
          echo '</noscript>'; exit;
     }
}  

then call the above function  to the page you wish the redirect to happen on

eg: redirect("redirect.php");

Cannot access xampp from internet in Cent OS

Issue

I have xampp installed on Cent OS. I started the xampp server and tried to access it with localhost, it is working. But i cant access it using the system IP. I can ping the server.But I can't  access the server from any other computer on the network.

Solution

The default firewall of CentOS permits ssh input(tcp 22) and icmp(ping). Open a terminal and type

[root@ ~]# cat /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

Try at first stopping your firewall issuing the following command:

[root@ ~]# /etc/init.d/iptables stop

Now, test if you can access your XAMPP server.
Go to File System -> etc - >sysconfig
Open iptables. Remove the below line

-A INPUT -j REJECT --reject-with icmp-host-prohibited

 Add the below new line

iptables -A INPUT -m state --state NEW -m tcp -p tcp -m multiport --dports 80,443 -j ACCEPT

It enables the ports you need to access(80 , 443).
Now your iptables looks like

# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp -m multiport --dports 80,443 -j ACCEPT
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

Save the file and close it.
Start your firewall issuing the following command:

[root@ ~]# /etc/init.d/iptables start

Now  you can access your XAMPP server using your macine ip address