html - how to format web page content loaded from javascript? -

I have a webpage that displays a web form whose source is Javascript

By default it Keeps this screen in the top left corner of the screen. How to the horizontal and vertical center on the screen?

I am confused because block & lt; Script & gt; In the section & lt; Body & gt; Instead of .

This form is generated by my email marketing service provider, and I do not have access to the code.

The complete HTML file is:

  & lt ;! DOCTYPE html & gt; & Lt; Html & gt; & Lt; Top & gt; & Lt; Script type = "text / javascript" src = "https: // app ...." & gt; & Lt; / Script & gt; & Lt; / Head & gt; & Lt; Body & gt; & Lt; / Body & gt; & Lt; / Html & gt;  

Without realizing what your javascript is doing, it is difficult to answer Although normalized is the answer to your problem using CSS, you can do this in the top section of your HTML document that & lt; Style & gt; tag (see the code below) or & lt; Link & gt; An external stylesheet by using >

Check W3 to start learning more about CSS:

Real CSS properties will require you to vary , But shows the use of the conversion: Translate to center an element vertically and horizontally.

  & lt ;! DOCTYPE html & gt; & Lt; Html & gt; & Lt; Top & gt; & Lt; Style & gt; / * This is a class that you will add to the original HTML tag of your form / / {status: relative; Left: 50%; Top: 50%; Conversions: translations (-50%, - 50%); } & Lt; / Style & gt; & Lt; Script type = "text / javascript" src = "https: // app ...." & gt; & Lt; / Script & gt; & Lt; / Head & gt; & Lt; Body & gt; & Lt; / Body & gt; & Lt; / Html & gt;