GuyFromChennai http://www.guyfromchennai.com Blog of a Web Craftsman Mon, 15 Mar 2010 04:18:44 +0000 en hourly 1 http://wordpress.org/?v=abc Snippet to Dynamically add rows to a table http://www.guyfromchennai.com/?p=146 http://www.guyfromchennai.com/?p=146#comments Fri, 08 Jan 2010 11:20:16 +0000 Kumar S http://www.guyfromchennai.com/?p=146 This code snippet will help you to add rows dynamically in a html table.


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Insert Table Row using DOM</title>
<script language="javascript">
function addRow()
{
var tbody = document.getElementById("table1").getElementsByTagName("tbody")[0];
var row = document.createElement("TR");
var cell1 = document.createElement("TD");
var inp1 =  document.createElement("INPUT");
inp1.setAttribute("type","text");
inp1.setAttribute("value","New row");
cell1.appendChild(inp1);
var cell2 = document.createElement("TD");
cell2.innerHTML = "label3";
var cell3 = document.createElement("TD");
cell3.innerHTML = "label4";
row.appendChild(cell1);
row.appendChild(cell2);
row.appendChild(cell3);
tbody.appendChild(row);
//alert(row.innerHTML);
}
</script>
</head>
<body>
<tableid="table1">
<tbody>
<tr>
<td><inputtype=textvalue="Original Row"></td>
<td>label1</td>
<td> label2</td>
</tr>
</tbody>
</table>
<inputtype="button"value="Insert Row"onClick= "addRow();">
</body>
</html>

Most of the code is self explanatory, so am leaving it unexplained. If anybody needs help, post your questions, will help you.

]]> http://www.guyfromchennai.com/?feed=rss2&p=146 2 Get computed Width of an HTML Element http://www.guyfromchennai.com/?p=143 http://www.guyfromchennai.com/?p=143#comments Fri, 08 Jan 2010 11:09:35 +0000 Kumar S http://www.guyfromchennai.com/?p=143 This function will help you to get the computed width(actual width) of an HTML Element/Object. For example you may be using a div to show some contents inside that. But want to calculate the actual width of the div after loading the contents inside it. There comes this function to help you.
function getComputedWidth(theElt){
var browserName=navigator.appName;
if (browserName=="Microsoft Internet Explorer"){
var is_ie=true;
} else {
var is_ie=false;
}
if(is_ie){
tmphght = document.getElementById(theElt).offsetWidth;
}
else{
docObj = document.getElementById(theElt);
var tmphght1 = document.defaultView.getComputedStyle(docObj, "").getPropertyValue("width");
tmphght = tmphght1.split('px');
tmphght = tmphght[0];
}
return tmphght;
}
< div id="demo" onclick="alert(getComputedWidth('demo'));">hello there< /div>

To know the computed height of an element see here

]]> http://www.guyfromchennai.com/?feed=rss2&p=143 1 Get computed Height of an HTML Element http://www.guyfromchennai.com/?p=139 http://www.guyfromchennai.com/?p=139#comments Fri, 08 Jan 2010 10:56:30 +0000 Kumar S http://www.guyfromchennai.com/?p=139 This function will help you to get the computed height (actual height) of an HTML Element/Object. For example you may be using a div to show some contents inside that. But want to calculate the actual height of the div after loading the contents inside it. There comes this function to help you.


function getComputedHeight(theElt){
var browserName=navigator.appName;
if (browserName=="Microsoft Internet Explorer"){
var is_ie=true;
} else {
var is_ie=false;
}
if(is_ie){
tmphght = document.getElementById(theElt).offsetHeight;
}
else{
docObj = document.getElementById(theElt);
var tmphght1 = document.defaultView.getComputedStyle(docObj, "").getPropertyValue("height");
tmphght = tmphght1.split('px');
tmphght = tmphght[0];
}
return tmphght;
}

< div id=”demo” onclick=”alert(getComputedHeight(‘demo’));”> hello there< /div>
Thanks to Richard A who made the code complete to run as a demo.

To know the computed width of an element see here

]]> http://www.guyfromchennai.com/?feed=rss2&p=139 1 Structured Process of Developing a Web Application http://www.guyfromchennai.com/?p=134 http://www.guyfromchennai.com/?p=134#comments Thu, 07 Jan 2010 04:16:54 +0000 Kumar S http://www.guyfromchennai.com/?p=134 A small presentation that will help the beginners to understand the process of developing a Web application.
I did this presentation for the my Team @ Office to give them the idea of the whole process.

]]> http://www.guyfromchennai.com/?feed=rss2&p=134 0 Advanced Techniques in PHP – Part 1 http://www.guyfromchennai.com/?p=131 http://www.guyfromchennai.com/?p=131#comments Thu, 07 Jan 2010 04:05:53 +0000 Kumar S http://www.guyfromchennai.com/?p=131 Here I tried to explain two advanced techniques in PHP.
1. Backtracing
2. Method Chaining

]]> http://www.guyfromchennai.com/?feed=rss2&p=131 1 Webservice – a brief Introduction http://www.guyfromchennai.com/?p=123 http://www.guyfromchennai.com/?p=123#comments Thu, 07 Jan 2010 03:48:47 +0000 Kumar S http://www.guyfromchennai.com/?p=123 Recently I prepared this presentation for a small lecture for my team, to give info about web services.
Hope this will be helpful to others too. I tried to explain what is an Webservice, how and where it is used, How it works, Necessary thing to know to develop a webserice, etc.

]]> http://www.guyfromchennai.com/?feed=rss2&p=123 0 SVN Quick Installation Guide in Ubuntu http://www.guyfromchennai.com/?p=118 http://www.guyfromchennai.com/?p=118#comments Wed, 16 Dec 2009 00:58:00 +0000 Kumar S http://www.guyfromchennai.com/?p=118 For all of the installation and configuration process, you need to login as root.

Installation

apt-get install subversion (this will install the subversion package) Install any other dependencies if any as required for your system.

Server Configuration

The following steps assume that, the necessary packages are installed. Now we will create the folders and the repository. The SVN repository can be placed in several places in the server. Most common places are /var/svn/ , /svr/svn/,  /home/svn/ etc.

First of all create a new user group named “subversion”
addgrp subversion
Then add youself and the www-data ( the apache user) to this groups. You can do this by doing the following steps

1 Choose System > Administration > Users and Groups from your Ubuntu menu.
2 Select the Group tab
3 Click the ‘Add Group’ button
4 Name the group ‘subversion’
5 Add yourself and www-data (the Apache user) to this group .
Note: As default, the user configuration does not show system users. To see the Apache user in this list, do the following
a) Start gconf settings editor: Alt+F2 gconf-editor Enter.
b) In the tree, locate /apps/gnome-system-tools/users.
c) Select the “showall” check-box.

Now logout and login again in order to the above changes to be applied.
Now we will create the folder where you can place the SVN repository.

mkdir /home/svn
cd /home/svn
mkdir projectname
chown -R www-data:subversion projectname
chmod -R g+rws projectname<-This command will set the gid for proper permissions on all new files added to your SVN repository.

Now issue the following command to create the SVN repository
svnadmin create /home/svn/projectname
chmod -R g+rws projectname Issue this command again, because svnadmin will create folders and files without the write access to the group.

Importing the Project into SVN

Now go the folder where your project folder is present. Then issue to following command to import your project into SVN repository.
svn import projectnamefile:///home/svn/projectname –m “Initial checkin of projectname into SVN”

Creating Users

Now we have created the repository and imported the project into it successfully. Now we have to control the access to the repository by creating users.

If the SVN is just now installed the passwd file will not exist and it should be created first,   under the /etc/subversion folder. This is the file that will contain the authentication details for the users.

to create the the password file, use the command
htpasswd –c /etc/subversion/passwd username (Enter the username here)

this will prompt us to enter the password for the user. Enter the password. Now the user is added. To add more users use the same command above without using the –c switch. For example to add another user, use the following.

htpasswd /etc/subversion/passwd username2 (Enter the second username here)

Checking out from Repository

We have created the repository, imported out project into SVN and created the users also. Now to check with the installation and repository, we have to checkout our project from the repository. Go to any of your working folder(not to the svn repository folder) first. To checkout use the following command

svn co file:///home/svn/projectname (this will checkout the projectname from SVN repository)

That’s it we are done with the our basic things to use SVN.  To access SVN over various protocols like http://, https://. svn:// and svn:+ssh// we can refer ubuntu or SVN documentation. For an example I’ll explain how to access our SVN repository over http:// (WebDAV).

Access the SVN via WebDAV (http://)

To access the SVN repository via WebDAV, we must configure the Apache server.
First we have to install the libapache2-svn package
apt-get install libapache2-svn

Then add the following snippet to the /etc/apache2/mods-available/dav_svn.conf file.

<Location /svn/projectname>
DAV svn
SVNPath /home/svn/projectname
AuthType Basic
AuthName “projectname subversion repository”
AuthUserFile /etc/subversion/passwd
<LimitExcept GET PROPFIND OPTIONS REPORT>
Require valid-user
</LimitExcept>
</Location>

Hope this will help somebody who would like to get all the basic, necessary steps to start using the SVN. Let me know your feeback.

For further reference see the following links

]]> http://www.guyfromchennai.com/?feed=rss2&p=118 0 Installing Apache,PHP5,MySQL on Ubuntu http://www.guyfromchennai.com/?p=112 http://www.guyfromchennai.com/?p=112#comments Tue, 27 Oct 2009 08:03:28 +0000 Kumar S http://www.guyfromchennai.com/?p=112 Apache
sudo apt-get install apache2

PHP
sudo apt-get install php5
sudo apt-get install libapache2-mod-php5

sudo /etc/init.d/apache2 restart

MySQL
To install the MySQL Server and Client packages.
sudo apt-get install mysql-server mysql-client
This will install the mysql server and client packages.
By default, recent Ubuntu/Debian systems install a MySQL Server from the 5-branch.

Set MySQL Root Password
By default, the root account of the MySQL Server is empty. To set the mysql root password do the following.
sudo mysqladmin -u root -h localhost password ‘mypassword’ #replace the ‘mypassword’ with your password.

Connect to MySQL from PHP / Ruby
Now you have Apache+PHP already installed, and want to connect to MySQL from PHP scritps.
For that you have to install one library, which is used to connect to mysql from PHP. Use this command to install the library.

sudo apt-get install php5-mysql

In case you are using Ruby, use the command
sudo apt-get install libmysql-ruby to connect to MySQL from Ruby.

Note : while restarting the apache if you get the following error
apache2: Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName

then open the /etc/apache2/apache2.conf file and add the following line
as the last line

ServerName “YourSitename or Servername”

save the file and restart the apache by giving the /etc/init.d/apache2 restart command, you will not get the error anymore.

To Install MySQL Query Browser, an GUI for MySQL

sudo apt-get install mysql-query-browser

After installation, to start MySQL Query Browser go to Applications > Programming > MySQL Query Browser.

Install PHP-GD Library

The GD Graphics Library is useful for dynamically creating, manipulating images. You will need to compile PHP with the GD library of image functions for this to work. However Ubuntu (and Debian) comes with package called php5-gd

To install GD for PHP use the following command.

sudo apt-get install php5-gd

I’ve collected the information from net which are required while installing and configuring Apache, PHP, MySQL and given here. Hope this will help for somebody who can get all information at one place.

]]> http://www.guyfromchennai.com/?feed=rss2&p=112 3 Check if a firefox addon is installed or not http://www.guyfromchennai.com/?p=104 http://www.guyfromchennai.com/?p=104#comments Mon, 26 Oct 2009 08:31:08 +0000 Kumar S http://www.guyfromchennai.com/?p=104 While trying to check if one of my firefox add-on is installed or not, I found that, Chrome resources can no longer be referenced from within <img>, <script>, or other elements contained in, or added to, content that was loaded from an untrusted source. This restriction applies to both elements defined by the untrusted source and to elements added by trusted extensions.

Before firefox 3 we were able to check if a firefox add-on is installed or not as following.
using an image tag to load an image in the firefox add-on.
Once loaded trigger the onload event to verify the add-on is loaded.
For example,
< img src=”chrome://youraddonname/content/skin/images/anyimagefilename” width=”0″ height=”0″ onload=”function call here()” style=”visibility:hidden” >;

But this stopped working after firefox 3 and later versions due to security restrictions.
And the extensions won’t interact with the web page in any way.

This caused my add-on checking scripts stopped working.
While digging through the Google, finally found a way to allow interaction with the chrome resources from developer.mozilla.org site.
It is “contentaccessible” flag, which allows the user scripts to check if the add-on is installed or not.

Please note that, The contentaccessible flag applies only to content packages: it is not recognized for locale or skin registration.
However, the matching locale and skin packages will also be exposed to content.

Change your chrome.manifest file as follows

content youraddonname chrome/content/
# Because older versions of Firefox do not understand the contentaccessible flag, any extension designed to work with both Firefox 3 or above
# and older versions will need the above line too

content youraddonname chrome/content/ contentaccessible=yes

Package your add-on and install the new version of your add-on.
Restart firefox.
Now you will be able to check the add-on is installed as following

< img src=”chrome://your add-on name/content/skin/images/anyimagefilename” width=”0″ height=”0″ onload=”function call here()” style=”visibility:hidden” >

For example

var isInstalled = false;

function checkAddon(){
isInstalled = true;
alert(‘Your addon is installed’);
}

< img src=”chrome://youraddonname/content/skin/images/anyimagefilename” width=”0″ height=”0″ onload=”javascript: checkAddon()” style=”visibility:hidden” >

You can use the variable isInstalled for later use.

Hope this will help others also, who are also trying like me.

]]> http://www.guyfromchennai.com/?feed=rss2&p=104 2 Cannot load mysql extension. Please check your PHP configuration http://www.guyfromchennai.com/?p=101 http://www.guyfromchennai.com/?p=101#comments Mon, 22 Jun 2009 12:16:15 +0000 Kumar S http://www.guyfromchennai.com/?p=101 Everytime I install PHP, MySQL in windows boxes I used to get the error message “Cannot load mysql extension. Please check your PHP configuration“. This is because i’d forget to do the necessary steps.

While wandering thru sites most of the people were looking for the same issues.So decided to write a simple post with the necessary steps to solve this while installing PHP, MySQL in a linux box.

PHP.INI settings

1. Modify extension_dir = “./” to extension_dir = “c:/PHP/ext”
2. make sure php_mysql.dll file is inside the folder c:/PHP/ext
3. uncomment the line ;extension=php_msql.dll i.e., remove the comma in the line. so that line will look like
extension=php_msql.dll

Others
4. Copy the libmysql.dll file to C:\WINDOWS folder
5. restart Apache Service

]]> http://www.guyfromchennai.com/?feed=rss2&p=101 3