I recent ran into an interesting IE bug involving the following bit of html code:

<a href="javascript: void(0);" onclick="dosomething();">click me</a>

I honestly did not write this one but I will leave names out of this to protect the innocent =)

The void(0) JavaScript code is usually used to prevent loading or reloading of the page when the user clicks a the link.

What we were trying to do here was have the dosomething JavaScript function execute when a user clicks on the link. This works fine in FireFox, Chrome, Safari but not IE. When a user clicks on the link in IE, nothing happens: i.e. (no pun intended) the JavaScript does not execute.

It took us a good amount of time to realize what the issue was with IE. It turns out that the void(0) function was preventing the onclick event to fire.

Although it may not be pretty, this is what we ended up doing and it appears to be cross-browser friendly:

<a href="<?=$_SERVER['PHP_SELF'];>#" onclick="dosomething();">click me</a>

Anyway, I hope this helps someone out there in the universe.

I was looking for a way to order the rows randomly in a MySQL query and the solution was not easy for me to come by. I am posting the solution here in hopes of helping others.

1
2
3

SELECT * 
FROM my_table
ORDER BY RAND()

RAND() returns a random floating-point value but functions to randomly order the selection of rows in the above usage.

If you combine the query with LIMIT, you will end up with a random selection of rows from your table.

1
2
3
4

SELECT * 
FROM my_table
ORDER BY RAND()
LIMIT 3

Assuming you have more than 3 rows in your table, you will always get 3 random rows from the query.

Let’s say you have the following PHP code that extracts the date from the times table in your MySQL database. The date is of timestamp type which has the following format: ‘YYYY-MM-DD HH:MM:SS’ or ‘2008-10-05 21:34:02.’

1
2
3
4

$res = mysql_query("SELECT date FROM times;");
while ( $row = mysql_fetch_array($res) ) {
   echo $row['date'] . "<br />";
}

Continue reading →

Let’s say you have the following table called votes that keeps track of how people voted and you want a query to count the number of votes for you instead of having to loop through all the rows with a counter in PHP.

Continue reading →

JavaScript has a built-in function called confirm which takes a string argument that poses the question to the user and gives them the option to click the OK or Cancel buttons and returns true if the user clicks OK.

Have you ever had to access a parent node from a given child node? In this example, we are going to traverse up the DOM tree starting from the button to look for the parent node with the name attribute itsMe.

I have more than 5 years experience as a bioinformaticist parsing and analyzing sequence data and designing/managing databases. I have a very strong background with regular expressions and scripting languages such as Perl and PHP. If you have some kind of text data that requires parsing or reformatting in any way shape or form, do not hesitate to contact me.

I can parse your data and give you the results or I can even design a simple drag-and-drop executable that will take your input file (or even a template file) and automatically output the result file for you.

Do you have a form with checkboxes or radio buttons that you would like to loop through via JavaScript? This JavaScript function will do just that!

This is a simple example of implementing a calculator with JavaScript and HTML. This calculator will only have the division, multiplication, addition, and subtraction operators but you can easily tack on more functions if needed.

This is an example of adding dynamic content via JavaScript by allowing the user type in the actual content.

This JavaScript demo verifies that an email address is in the correct format and that the user has typed in the same address in both fields to prevent mistyping of the address. I have borrowed the regex for verifying the correct email format from a different site.

This post is in response to one of the comments on have received regarding the removal of elements via JavaScript. I have taken the original function posted and edited it a little bit for the demo.

This is a neat little script that demonstrates two things:

1) Find - If only the Find box is filled in, then the findMyText() JavaScript function will just perform a find for the div that is given. If there is a match, the text will be highlighted and marked in bold.

2) Find and Replace - If both the Find and Replace boxes are filled in, then the findMyText() JavaScript function will do just that.

There is a rare need for this type of functionality but I have found myself in a couple of situations where I needed it. Here is a quick demo of a button click that is simulated from another event handler. In this case, the button click is invoked by checking a checkbox.

Here is a quick demo of the select all or none JavaScript function that automatically toggles all of your checkboxes in a given form.

Are you looking for a simple way to verify a form that you have? The example below demonstrates some of the common techniques used in verifying a form. Test out the form by leaving at least one of the fields blank before you submit the form.

The Document Object Model (DOM) allows for dynamic styling because it makes all HTML elements and attributes readily accessible using JavaScript. Here is a simple demo of how powerful this technology can be:

Not all forms are meant to be static. Sometimes, you want to allow the users to add certain parts of the form as they need them. Here is a nice example of dynamically adding inputs to your form as users need them. In addition, an input limit has been implemented in the script and it is set to 3.

Are you trying to find a way to hide and show your content? The demo below shows a simple yet elegant way of toggling your content and toggling the control text via Javascript and styling.

I have found myself in a couple of situations where I needed a simple dynamic javascript menu where the user would make a selection from one select list and depending on what the user selected from the first select list a second list would offer further options. Here is a perfect example: