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Javascript parseInt Hilarity

What do you think this bit of javascript code returns?

parseInt(’09′)

My guess is it returns the integer 9 as parseInt() is meant to turn strings to integers. In actual fact it returns zero. Nothing. Nada. It took me a bit of digging to find out why. The reason it returns an unexpected result is one of those situations where the javascript parser attempts to be clever, but gets it wrong. You see parseInt actually has an optional second parameter, called ‘radix’. This specifies the base of the number system to use, and if you dont specify it, the javascript parser makes a ‘best guess’. The rules are:

• If the supplied value starts with ‘0x’ then the parser guesses it to be a hex value.
• If it starts with a zero, the parser guesses it is base 8, octal.
• Anything else is guessed as decimal.

So if we pass in ‘09′ without an optional radix, the parser thinks we are working in base 8, and as 9 doesnt exist in octal, it actually returns zero. Strange!

TinyMCE – A Common Sense Configuration

TinyMCE is an open source WYSIWYG editor that is pretty popular, and used in many applications including being the editor installed into Wordpress. It’s small and gets the job done. The only downside is that it’s a pig to configure and the documentation is of a chocolate fireguard caliber. So here, if anyone wants it, is a TinyMCE configuration block I knocked together that contains all the stuff you need to act as a web based content entry text area. In fact, it’s an exact clone of the Wordpress editor.

    <script type=”text/javascript”>
        tinyMCE.init({
            mode: “textareas”,
            theme: “advanced”,
            theme_advanced_toolbar_location: “top”,
            theme_advanced_toolbar_align: “left”,
            theme_advanced_buttons2 : “”,
            theme_advanced_buttons3: “”,
            plugins : “inlinepopups”,
            dialog_type : “modal”,
            theme_advanced_buttons1_add: “bullist,numlist,blockquote,image,link,unlink,code  “,
            theme_advanced_disable: “formatselect, fontselect, fontsizeselect, styleselect, justifyfull  ”

        });
</script>

JQuery Pager Plugin

I’ve just knocked together a JavaScript pager for use in an application I’m working on and thought it may be of use to other people. I’ve therefore converted it to a jQuery plugin and released it under joint MIT and GPL licenses and it is entirely free for you to use or mess about with.

You can see a demonstration of it in action at http://jonpauldavies.github.com/JQuery/Pager/PagerDemo.html and visit my GitHub repository at http://github.com/jonpauldavies/jquery-pager-plugin/tree/master to download it.

Usage is very simple indeed. You just give it the number of pages to view, the current page, and a callback method to fire when the pager gets clicked.

Amazon.Com Addiction Continues Unabated….

I pay a quick visit to Amazon to get Kitty a few books and before you know it I’ve dropped an extra 70 quid on 3 JavaScript / JQuery books….

I have not had time to review them fully, but JQuery in Action is a thorough trawl through the functionality and use cases of this continually impressive library. I’ve got a pretty firm grasp of JQuery but my entire knowledge is built from blog posts so felt I needed something a bit more solid and this seems to fit the bill.

The JQuery Reference is very thin for a technical book and has yet to prove it’s worth now that we have decent JQuery intellisense in Visual Studio. I’ll have to wait and see how it pans out.

Lastly, Pro JavaScript Techniques is an overview of the ‘modern’ uses of the language, and how it has adopted several OOP paradigms as true client side development has matured in recent years.
If you are thinking of putting any of these on your Christmas list, I’d order them JQuery in Action, Pro JavaScript Techniques and The JQuery Reference – in order of usefulness.