Droj's Javascript Evaluator Tool

When learning Javascript, one of the most valuable tools you can have is a way to run snippets of code on the fly, without editing a file, then saving it, then reloading the page in your browser. You can run individual Javascript lines with browser development tools, but they're not as nice as having a Javascript "scratchpad" to try stuff out on.

Using POST to Send Form Data to a Servlet

Ajax is a great way to make your pages more dynamic. When using ajax, it's common to send data to your servlet in url-encoded form using a GET request. But there can actually be issues with sending information in GET requests. It's generally better practice to send data as a POST request, but there's one subtle detail required to make it work.

msxml3.dll: The system cannot locate the resource specified

I recently started getting this error in my Ajax application:

msxml3.dll: The system cannot locate the resource specified

Cannot define a function with window.eval() in IE 7

Sometimes it's useful to evaluate a string in Javascript. There a variety of reasons why one would want to do that, and it's reasonable to expect that the code would be evaluated in the same way as the code in your .js files. I needed to evaluate some code using the window.eval function in Javascript. It worked fine, until I got an error when the evaluated string tried to define a function.

How to Get the CURRENT Style of an Element in Firefox

I was trying to write some Javascript to get some style information about an HTML element. My instinct was to get the element object and access its 'style' property. But this only seemed to work some of the time, which was particularly frustrating! Eventually, I figured it out...

How 'closures' work in Javascript (and Perl)

When I was learning Perl, the concept of a "closure" was one of the more difficult for me. And the first time around, I didn't really get it. So, I put it aside for later and didn't really use them. It then promptly fell to the bottom of the pile and slipped through the cracks. I later started writing a lot of Javascript and re-encountered closures. This time, I was determined to understand what they are and how they work.

Adding Derby DB support to Apache Tomcat

I'm creating a web application that is really just made up of JSPs, servlets, html, Javascript, and a Derby database. I'd like to use Apache Tomcat, because it integrates with Netbeans, and is lighter weight than a full-blown EE server. But Tomcat doesn't ship with Derby.