Forms looks different on Explorer vs Mozilla

I have a form where fields have a specific number of entry size, ie PCode is P99999. On Firefox this looks fine but when I open the same form on Explorer 9 the fields are smaller even though the page size is the same (see example). Not sure why it acts different.

Maybe the best explanation to this is found on this article I found over the internet: http://www.smashingmagazine.com/2010/06/07/the-principles-of-cross-browser-css-coding/

See, HTML and CSS, especially on forms, appears differently on different web browsers. 

I have cloned you form so I can test it on each browser and here's what I found out. 

Internet Explorer:

Mozilla FireFox:

Google Chrome:

There are ways for you to apply CSS that will affect the form only when it is opened using Internet Explorer. 

You can check out this article: http://codemug.com/html/css-hacks-for-ie6ie7ie8ie9-and-ie10/

Or you can have the other way around. Edit your form so it should fit IE and place a code that will change the form's width when opened using FireFox.

https://css-tricks.com/snippets/css/css-hacks-targeting-firefox/

CSS codes can be added on your form using this guide: How-to-Inject-Custom-CSS-Codes

As for the Result: 

Internet Explorer: 

FireFox:

I hope this helps. Let us know if you need any further assistance. Thank you.