What disadvantages are there to the <button> tag?

Question

I started using a diagnostic css stylesheet, e.g. http://snipplr.com/view/6770/css-diagnostics--highlight-deprecated-html-with-css--more/

One of the suggested rules

Answer 1

as far as I am concerned the difference between submit and button tags is this: gives you the option to have different text displayed than the element's value

Let's say you have a list of products then next to each product you want a button to add it to the customer's cart:

product1 : 
product2 : 
product3 : 

then you could do this:

 add to cart 

Now the problem is that IE will send the form with value="add to cart" instead of value="product2"

The easiest way to workaroound this issue is by adding onclick="this.value='product2'"

So this:

 add to cart 

will do the trick on all major browsers - I have actually used this on a form with multiple buttons and works with Chrome Firefox and IE