The reading level for this article is Novice
Using Javascript in Your HTML Email
Since Javascript’s are mainly a unique and proprietary element, and by this we mean that you can write 100 different scripts which all do basically the same thing but in a different manner, complex JavaScripts will always have trouble in your HTML email.
Due to the wide variety of email clients, browsers, security settings, updates, and service packs installed, it is difficult to predict how a script will execute against any given email client. Javascripts can cause browsers & Outlook 2000 to disable and active scripting contained in an email document (there has been an increase in email security due to malicious scripts).
For more information on Microsoft Outlook & Office Security visit:
Outlook E-mail Security Update Information
http://support.microsoft.com/support/kb/articles/q262/7/01.asp
How Outlook Renders HTML
http://support.microsoft.com/support/kb/articles/q249/9/72.asp
You would be wise to test any Javascript you wish to include in a mailing. Not all email clients can handle the scripts, and most web-based systems disable scripts as a general rule to prevent malicious code from being executed on a system.
Javascript Navigation forms such as jumpmenu forms can easily be use, but even these will only work in non web-based email clients. Most other navigation forms are not supported because they do not work on the majority of web-based email clients.
Most Forms, which use the GET/POST method, will render and test correctly in web-based email clients.. You can often use this to get around many Javascript problems in HTML email.
Remember! Most web-based email browsers are a <FORM> themselves and use Javascript to power their product in some way or another. Your script has to be fairly inoccuous in order to not interfere with their product.
We’ll be providing some more examples as we expand of this collumn in the near future.
In the meantime, here is a list of HTML email FAQs & Resources