These web pages require JavaScript (also called 'active scripting') to be enabled on your browser. Some of the web pages require JavaScript version 1.5. The box below tells you whether JavaScript is running, but it does not tell you which version you have got. If you were referred here from another page on the site, it is likely a) that you do not have JavaScript enabled or b) that your browser does not support the version of JavaScript that is needed. Also see: Cookies.

What is JavaScript?

JavaScript (JS) is a scripting language that allows the web programmer to write small programs that run inside your web browser, and which allow it to perform complicated actions. For example, when you are asked to type a number into a web form (e.g. an order quantity on a shopping page), a small JS program could check that you have typed a valid number and could warn you if you have not.

Which Version of JavaScript do I need?

Some pages on this site require JavaScript 1.5, JScript 5.5 or compliance with ECMA v3. That's the technical bit, but its not so easy to determine which version your browser supports. In practice this version of JavaScript is supported by "all modern browsers". If you have been directed to this page because your browser does not support the required version then the only answer is to upgrade your browser or to change to a different brand of browser.

Why does this web page tell me that JavaScript is not running?

You probably have your security settings set too high. (Alternatively, your browser could be a very old version or a non-Windows version that does not support the necessary version of JavaScript). Running JavaScript within your web browser rarely poses any security problem because JS is unable to access privileged information on your computer - it is restricted to running 'inside' your browser. When problems do arise it is usually because of bugs in your browser - so make sure you have the latest version installed. Occasionally, a malicious programmer can exploit your ignorance or naivety of computers and the Internet; and this is sometimes aided using legitimate JavaScript programs. If you want to know more, read the Wikipedia entry on JavaScript.

Should I enable JavaScript?

This is obviously your decision, but without it you will not be able to use some of our web pages. If you do enable JS and you run into problems it would be unrealistic to expect the responsibility for your woes to rest with anyone other than yourself. It is clearly your responsibility to ensure that you maintain a safe software environment on your computer. Commonly given advice includes such actions as to always install the latest security patches and software versions, to use reputable anti-virus software and to maintain a firewall.

How do I enable JavaScript?

To enable JS you will need to search your browser's Options or Preferences menu. In Firefox this is straightforward but in Internet Explorer the JS 'switch' can be difficult to find.

For Internet Explorer: From the Tools menu, select Internet Options and click the Security tab. Next, either reduce the security setting for your Internet Zone as a whole, or click on Custom Level and search for the Scripting heading near the bottom of the list. (Note that it might not mention JavaScript by name). In the Active Scripting sub-heading, select Enable to enable JavaScript.

For Firefox: Tools / Options / Content / Enable JavaScript.

For Chrome: Click the Menu button (Three bars, like this:), select Settings, then Show Advanced Settings. Scroll down to Privacy and click the Content Settings button. Then scroll down to JavaScript and make your changes.

Why have I never seen this warning before?

Many web pages make extensive use of JavaScript but, commonly, programmers do not bother to check whether your browser can cope with their code. If you visit a web page and it behaves strangely, or it seems to be badly presented, then this could be because it requires the use of JavaScript. We are trying to ensure that our programs fail gracefully, which is why you are reading this warning.

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