How To Prevent Duplicated Get Param

I have a form, it’s method is GET. Can’t change to POST, due to several reasons.

So when I pick a value from a combo box (that sorts the products), my address



Because the form is still visible, when I pick another value, the address becomes:

and so on…

Is there a trick to prevent the accumulation of params?

Seems like your form "action" parameter is empty.

Set it to required value.