Difference in links to a particular page

When I open the html file in my browser the link looks like file:///C:/Users/Random/Project-name/forgot-password.html and the page loads correctly too...but when I fill the credentials and click on the submit button the page reloads(which is unexpected) and now the link looks like file:///C:/Users/Random/Project-name/forgot-password.html?# and now when I fill the credentials and click on the submit button now the page does not reload and I get the expected output. So would anyone help me with this ?

I want the page to work in the first time itself.