I was using <input type="button" value="label" onclick="javascript:xxx" /> to launch &#106avascript events in my page. It struck me that a better idea would be <button onclick="javascript:xxx">label</button> since the inputs didn't really belong to a form, and the proper buttons can be CSS'd. There was one odd difference, though. When any button was clicked, now the address bar fills up with ?name=value&name=value... for all inputs on the page. Why should this happen and how do I stop it?

Well, AFAIK inputs of type button can't contain other HTML such as images, and i'd have to type 'class="but"' or something for each of many buttons and I'd rather have a button{} entry in the .css.

It may well end up being the workable solution, but I'd still like to know why it's happening. They're not submit inputs.

Do you have any form tags lingering around on your page? Buttons often become a default form submit widget. And else try:

<button onclick="javascript:xxx; return false;">Label</button>