Vba Macro to save file on folder

[msqueiros]

I'm starting to learn how to work with VBA Macros and I'm in a point that a can't move on, So I have an excel workbook with some user and pass from a website, in my macro a read that values and navigate to that website using IE, after the login a want to download a pdf file, that file is generated after pressing a button
HTML on that button:

<code><input class="tB" value="Emitir" *******="javascript:obterFormulario()" type="button"></code>

VBA to open pdf in a new window

<code>objIE.Navigate "javascript:obterFormulario('','')"</code>

I already try to use URLDownloadToFile but my pdf dont have a url or i cant find it If you guys can help me I really appreciate