When I started my new job, I had to make the transition from YUI to jQuery. I’d seen some jQuery code before (in fact, its terseness and use of $ as both an object and a function were easy to spot), but I wasn’t familiar with it. I actually thought that the query part of jQuery meant there was some kind of Standard Query Language interface. There isn’t, but there is a really cool CSS3 selector instead.

Turns out, I was a little disappointed; I wanted to use something query-based. So, I started to throw this script together. I call it JSQL. Below are some quick examples of what it looks like in action:

<br /> var results = JSQL(’SELECT * FROM #ft WHERE nodeName = “LI”);<br />

JSQL always returns an object with an error property that’s either Boolean false or a String stating what error occurred (for example, “Unknown command UPDAT3″). If it successfully retrieves or operates on elements, it returns a count:Number property with the number of elements and an elements:Array property with those elements.

Here are some interactive examples:

Example 1: Checkboxes

<br /> JSQL(’UPDATE #jsql-example-1 SET checked = true WHERE type = “checkbox”‘);<br />

Set Checked

<br /> JSQL(’UPDATE #jsql-example-1 SET checked = false WHERE type = “checkbox”‘);<br />

Uncheck

Example 2: Form Validation

<br /> JSQL(’UPDATE #jsql-example-2 SET parentNode.className = “error” WHERE value = “”‘);<br />

Highlight empty fields

<br /> JSQL(’UPDATE #jsql-example-2 SET parentNode.className = “” WHERE value = “”‘);<br />

Reset

Example 3: Removing Elements

<br /> JSQL(’DELETE FROM #jsql-example-3 WHERE nodeName = “STRONG”‘);<br />

Remove strong tags

In the spirit of jQuery, I also stuck in a quick each method which you can use to iterate through the returned elements immediately instead of setting up your own loop. The context is the current element (like jQuery) and the return value is still the same:

Example 4: Selecting Elements

<br /> JSQL(”SELECT * FROM #jsql-example-4 WHERE nodeName = ‘EM’”).each(function() {<br /> this.style.background = ‘#ffff00′;<br /> });<br />

Select & Operate

<br /> JSQL(”SELECT * FROM #jsql-example-4 WHERE nodeName = ‘EM’”).each(function() {<br /> this.style.background = ”;<br /> });<br />

Undo

I started coding this several months ago, and just recently decided to revisit it. I found the code hard to read myself when making some modifications before publishing it here. That typically means it’s poorly written. And I’m admittedly lousy at writing parsing code… so there’s that. I also doubt it’s realistic for any real-world websites (other libraries handle those jobs quite well), but I thought it would be fun to play with.

Some noticeable features lacking are equivalents to ALTER and INSERT INTO. I’ve also got it up on GitHub, so feel free to fork it, and maybe add those methods yourself!

• [Download jsql.js] (11k)
• [Download jsql-min.js] (3,661 bytes)