Here is a simple Javascript function to validate a date in US format.

function isDateValid(date) {
	//RegEx to validate date
	/*
	* ^[0-1][1-2] : The month starts with a 0 or 1 followed by either a 1 or a 2
	* [- / ]?: Followed by  an optional "-" or "/".
	* (0[1-9]|[12][0-9]|3[01]) : The day part must be either between 01-09, or 10-29 or 30-31.
	* [- / ]?: Day part will be followed by  an optional "-" or "/".
	* (18|19|20|21)\\d{2}$ : Year begins with either 18, 19, 20 or 21 and ends with two digits.
	*/
	var dateRegExPattern = "^[0-1][1-2][- / ]?(0[1-9]|[12][0-9]|3[01])[- /]?(18|19|20|21)\\d{2}$";
	if(date.match(dateRegExPattern)){
		return true;
	}else{
		return false;
	}
	
}

How to validate Date using Javascript Regular Expression is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

Are you looking for an affordable yet reliable web hosting company? Let me introduce you to eleven2.com. About 5 years ago I moved my website to them and since then I am one of their many happy and satisfied customers. While searching for a web hosting company five years ago to move my blogs from my previous host I stumbled upon eleven2.
Since I hadn’t heard of this company before I was somewhat reluctant to sign up with eleven2. So I emailed them few questions late one night and to my pleasant surprise they responded within few minutes. We exchanged few quick emails and they convinced me that eleven2 is a customer-centric host with 24/7 tech support. Fifteen minutes later I became their customer. I can vouch for their excellent customer service. I did not face any major issues but whenever I had a question or complaint they responded almost instantaneously. Tech support team is knowledgeable.
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Get 99% off first month of hosting service fee. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

1. Create and upload the standalone webpage to your domain.
2. Backup your index.php file in templates/YOUR_TEMPLATE_FOLDER.

3. Add following lines to the index.php file under the templates/YOUR_TEMPLATE_FOLDER.

Now when the visitors come to your website they will be taken to NEW_PAGE.php.
After the need to redirect the traffic is over simply replace the index.php file with the file you backed up in step 1.

Happy coding..

How to redirect homepage in Joomla is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

This program accepts input from the user and then prints out the largest and smallest numbers.

import java.util.*; 
public class NumberSorter{
	public static void main(String args[]){
	  double a, b, c, x, y;
	  Scanner console = new Scanner(System.in); 
	  System.out.print("Enter the first number: " ); 
	  a = console.nextDouble() ;
	  System.out.print("Enter the second number: " ); 
	  b  = console.nextDouble() ;
	  System.out.print("Enter the third number: " ); 
	  c = console.nextDouble();
	  x= Math.min(a, Math.min(b, c));
	  y= Math.max(a, Math.max(b, c));
	  System.out.println("\n" +x + " is the smallest number.\n" + y 
	                     +" is the largest number.");
	}
}

Hope you find this useful. Share your ideas on how else can we find largest and smallest values from a group of numbers Java.

Sort numbers in Java to find minimum and maximum values without using Array is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

So what is the difference between “==” and “equals()” and what is the correct method of comparing two string variables?

The == operator:

The “==” operator compares the references of two objects in memory. It returns true if both objects point to exact same location in memory. Remember that Strings are immutable in Java, so if you have a String variable str1 with a value of “abc” and then you create another variable str2 with value “abc”, rather than creating a new String variable with same value, Java will simply point str2 to same memory location that holds the value for str1.

In this scenario str1==str2 will return true because both str1 and str2 are referencing the same object in memory.

However, if you create a new variable using the String constructor, like String str3=new String(“abc”); Java will allocate new memory space for str3. Now although str1 and str3 have exact same value, str1==str3 will return false because they are two distinct objects in the memory.

The equals() method:

The equals method compare the text content or the value of two string variables. If both variables have exact same value, equals() will return true, otherwise it will return false.
So, str1.equals(str2) , str1.equals(str3), and str2.equals(str3) will all return true.
str1.equals(“xyz”) will return false.

Here is an example to help you understand the difference between “==” and equals().

public class StringComparison{
	public static void main(String args[]){
		String str1 =  new String("abc");
		String str2 =  new String ("abc");
		if(str1==str2){
			System.out.println("str1==str2 is true");
		}else{
			System.out.println("str1==str2 is false");
		}
		
		
		
		if(str1.equals(str2)){
			System.out.println("str1.equals(str2) is true");
		}else{
			System.out.println("str1.equals(str2) is false");
		}
		
		String str3="abc",
		str4 ="abc";
		if(str3==str4){
			System.out.println("str3==str4 is true");
		}else{
			System.out.println("str3==str4 is false");
		}
	}
}
 

Here is the output from this program.

 str1==str2 is false
 str1.equals(str2) is true
 str3==str4 is true
 

Most of the time you need to compare the values of the variable so you will need the equals() method. In situations where you need to check if two variables reference same memory location then you will use “==” operator.

I hope this will help you understand when to use “==” or equals() for Java string comparison.

Image credit: Martyne

Java String comparison. The difference between == and equals(). is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

Doctypes

If your website is not rendered properly by some browsers, the first thing you need to check is the first line in your HTML document.

The first line of every HTML document should have a valid DOCTYPE declaration. A missing or invalid DOCTYPE sends browsers in to the quirks mode and then the web browser uses its own methods to parse and render your page.

What is DOCTYPE?

A Document Type Declaration (DOCTYPE) informs the browsers which version of (X)HTML your web page is using. Browsers use this information to validate and render your documents. All compliant web pages must begin with a valid DOCTYPE declaration. If you don’t include a DOCTYPE declaration or if it is not valid, your web pages will not be validated and the web browser won’t be able to render your web pages properly.

Why DOCTYPE is important?

All standard-compliant browser need some information about the page to validate its content and then display it properly. There are several versions of HTML and XHTML and browsers need to know the version you are using.
A DOCTYPE tells browsers which (X)HTML version you are using and help them to render your page in standards–compliant mode. This will ensure that your pages are displayed by all browsers like you want them.

[ad#GreyLeft]But if you don’t include the DOCTYPE or if your DOCTYPE declaration is invalid, most browsers will assume that you are using an older version HTML and your page does not meet latest standards. The browser will then try to parse and render your page in backward compatible fashion (known as quirks mode) and may use browser-specific DOM.
Of course, you don’t want this. So save yourself some time and frustration by adding one of the following DOCTYPES in all your HTML page.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN"
   "http://www.w3.org/TR/html4/frameset.dtd">
	

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
	

I copied these DOCTYPE declarations from W3C website. You can find complete table of DOCTYPE declarations at http://www.w3.org/QA/2002/04/Web-Quality.

This one line in all your HTML pages will make your relationship with browsers a little less stressful. My advise to all web developers, “Don’t publish a web page without DOCTYPE.”

An HTML element you don't want to omit. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

Finally, I decided to get it down and settled on this elegant, free premium theme. I am still working on some minor customization but I believe this is a nice, professional-looking theme that meets my requirements.

Share your thoughts on this new design. Do you like the color scheme, page layout? What do you not like? What elements do you think I can change to further improve the look?

A fresh new look. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha

Onload

It is amazing that many web developers still use onload method embedded in the BODY tag, like

 <HEAD>
 <BODY onload="document.contact.userID.focus();">
  <form name="contact">
   <input type="text" name="userID" >
  </form>
  </BODY>
 </HEAD>

There are two problems with this line of code.

1. Embedding code (behavior) with HTML (structure) makes it difficult to maintain the page.
2. onload() method will executes only after the page is fully displayed.

Let’s see how to fix these problems.
Fixing problem # is quite simple. Just move your JavaScript code to the header section of you HTML page.

<HTML>
<HEAD>
<script language="javascript">
function setFocus(){
	document.contact.userID.focus();
}
</script>
</HEAD>
<BODY onload="setFocus();">
<form name="contact">
<input type="text" name="userID" >
</form>
</BODY>
</HTML>

Even better approach would be to move the code to an external Javascript file and add a reference to that file in the header section of the HTML document. For example, if the code is in script.js you can import the code like

<HTML>
<HEAD><script language="javascript" ref="scripts/script.js">
</HEAD>
<BODY onload="setFocus();">
<form name="contact">
<input type="text" name="userID" >
</form>
</BODY><
/HTML>

This approach will make your HTML code clutter-free and the code will be more manageable. But this does not address the fact the there is a delay in the exectuion of the code. onload method executes after the page is completely loaded. For instance, if you want to set focus to a text field on your web page using onload method, the foucs will be set after the page is completly downloaded.

If your web page is a simple text page with no images or multimedia elements then using onload might be OK. However, nowadays almost all web pages have at least few images, some even have embedded audio, video, Flash or other rich multimedia resources. These large resources take considerably long time to be fully loaded. And until all the content of the page is fully downloaded and the DOM tree is constructed, onload will not be fired.

Set focus to the text field without onload:

There is nothing wrong with the onload method, the problem is the large size of page elements that need to be downloaded by the browser. The browser needs to construct the DOM tree, load all the images and other multi-media resources and when everything is done then it will execute the onload method. A DOM tree is constructed instantly by the browser, but the large size of other elements take a while to be fully loaded. It means these external multilmedia files keep browser from executing the code triggred my onload event. The best approach would be to wait just long enough to let browser contstuct the DOM tree and then execute your code without waiting for all the objects to be completely downloaded. This can be done by using jQuery's ready() function.

  <script type="text/javascript" src="scripts/jquery-1.3.2.min.js">
  </script>
    <script type="text/javascript">
      jQuery(document).ready(function() {
        document.contact.userID.focus();
      });
    </script>

or more formally.

$(function(){
	document.contact.userID.focus();
}

So now your HTML code will be like

 <HTML>
 <HEAD>
  <script type="text/javascript" src="scripts/jquery-1.3.2.min.js">
  </script>
    <script type="text/javascript">
      jQuery(document).ready(function() {
        document.contact.userID.focus();
      });
    </script>
 </HEAD>
 <BODY >
 <form name="contact">
 <input type="text" name="userID" >
 </form>
 </BODY>
 </HTML>

Now our JavaScript code will be executed as soon as the DOM is fully constructed, without waiting for images and other multimedia resources. In this example the focus will be set to your input text field almost instantly and user can start typing in the information without waiting for rest of the page to be downloaded. This is a simple but effective way of improving your website's usability.

Why you should stop using onload method. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha


]]> http://www.zparacha.com/better-alternative-to-onload/feed/ 8 http://www.zparacha.com/better-alternative-to-onload/ http://feedproxy.google.com/~r/zparacha/~3/yyfx-kHDzio/ http://www.zparacha.com/google-says-goodbye-to-ie6/#comments Sat, 30 Jan 2010 17:31:31 +0000 Zaheer Paracha http://www.zparacha.com/?p=1119 Google says Adios to IE6. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha
]]>
Google agrees that the time has come for us to lay IE6 to rest. Google announced in a blog post that it will stop supporting IE6 from March 01, 2010. Google will start by phasing out IE6 support for Google Docs and Google Sites, but I believe eventually all Google products will stop supporting IE6.


From Google’s official blog:

Many other companies have already stopped supporting older browsers like Internet Explorer 6.0 as well as browsers that are not supported by their own manufacturers. We’re also going to begin phasing out our support, starting with Google Docs and Google Sites. As a result you may find that from March 1 key functionality within these products — as well as new Docs and Sites features — won’t work properly in older browsers.

Even Microsoft itself recommends users to stop using IE6. Many corporations have already stopped supporting or using IE6, with the addition of an Internet giant like Google I hope the drive to abandon the aging IE6 will get some momentum. Hopefully 2010 will be year where wen can move away from IE6. That would be an awesome news for all web developers.

What are your thoughts on IE6?

Image src: http://www.ferdychristant.com

Google says Adios to IE6. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha


]]> http://www.zparacha.com/google-says-goodbye-to-ie6/feed/ 3 http://www.zparacha.com/google-says-goodbye-to-ie6/ http://feedproxy.google.com/~r/zparacha/~3/7jOeW0OSWPc/ http://www.zparacha.com/free-color-tools-for-webdesigners/#comments Fri, 29 Jan 2010 06:03:07 +0000 Zaheer Paracha http://www.zparacha.com/?p=1061 Five free tools to choose perfect colors for your website. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha
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Rainbow colors


Color coordination plays a big role in the look and feel of a website. An appealing color scheme is an important prerequisite for eye catching web design. Dull or very sharp colors or mismatch colors will not only look ugly it may overshadow other nice elements of your website. Choosing vibrant, harmonious colors that are pleasant to eyes enhance the aesthetics appeal of a website. Following is a list of online resources you can use to construct the color schemes for your next web design project.


Kuler



Kuler is a featured-rich online color free tool from Adobe that you can use to create your color themes or browse through thousands of themes generated by community members. As a registered user you can save your themes and then view them in MyKuler. You can create themes using single color or by using color wheel. You can also extract color scheme from your images, for that you can upload your images or import them from Flickr. Kuler is my favorite.

ColorRotate:



Like Adobe Kuler, Colorrotate is also a free, online tool to generate color templates, but this is a 3D tool. Its intuitive 3D interface is fun to use and it enables you to quickly see the multidimensional nature of your colors and the relationships between colors. You can use its drag-and-drop option to adjust hue, brightness, and saturation. You can load color themes from you images. It also has a vast collection of community generated themes that you can browse to get some inspiration.

ColorSchemeDesinger



ColorSchemeDesigner is another free, online tool to generate color palettes. Its unique, easy-to-use color theme creator packs many useful featuers. You can generate single monochromatic, complimentary, triad, tetrad, analogic, and accented analogic color palettes. Not only you can create the color palette , you can also user their preview function to apply your palette to a dummy web page, to see how your colors will look on your website. This will definitely save many designers lot of time.
Another great feature is the ability to export your color palette as a Photoshop palette, HTML+CSS, XML, TXT, and GPL .
This tool does not work in IE6.

ColourLovers



If you need color inspiration, you will love ColourLovers. Designers from all over the world share their creative ideas on this website. It has over 286,866 members and showcase more than 2,407,124 colors, 1,090,882 palettes and 732,299 patterns. You can create your own color palettes or just pick one from this enormous collection.

COLOURlovers is a resource that monitors and influences color trends. COLOURlovers gives the people who use color – whether for ad campaigns, product design, or in architectural specification – a place to check out a world of color, compare color palettes, submit news and comments, and read color related articles and interviews.

4096 Color Wheel



If you don’t want all the bells and whistles of above mentioned tools, you may want to try Color Wheel. This is a simple web-based tool to view and choose web-safe colors. It offers you a palette of seven colors, displayed on the left side of the screen. You can change these 7 colors one by one by clicking on a color wheel. It is a nice little tool to generate a color palette.

What are your favorite tools for creating color schemes?

Five free tools to choose perfect colors for your website. is a post from: zParacha.com | Effective programming and blogging tips by Zaheer Paracha


]]> http://www.zparacha.com/free-color-tools-for-webdesigners/feed/ 17 http://www.zparacha.com/free-color-tools-for-webdesigners/