Is <button type=button> any different from a simple <button> with a blank or missing type attribute? MDN and the HTML5 spec say that type=button is for buttons whose purpose is to trigger custom JavaScript, but isn't that also what a <button> does by default?
Yep, there's a reason - but (usually) only if you're in a <form> element.
If you include a button in a form element without specifying it's just a regular button, it defaults to a submit button.
<form>
<button>I will submit the form when clicked!</button>
</form>
vs
<form>
<button type='button'>I won't!</button>
</form>
The first one is assumed to be type=submit since a type attribute hasn't been specified.
If you are not in a <form> element, the button won't have anything to submit, so it doesn't matter as much. :)
Semantics usually become important at some point in your application's lifetime, though, so it's a good idea to make a habit of specifying the type.
The only other reason that could be relevant is if there's a styling rule that specifies [type=button] or something. That's not recommended, though.
