Format of URL for advanced Google search engine query

I am trying to find the advanced search query for HTML to automatically search the results.

For example, a plain google.com query is https://google.com/search, while image search query is https://images.google.com/images

I can't find the query to automatically search the values from 4 text boxes through the Advanced Search engine.

The functionality I am looking for is that when I try searching for keywords from my web page it should go through the advanced search engine:

<form action="https://www.google.com/advanced_search?as_q=q&as_epq=r&as_oq=s&as_eq=t">

I found an alternative to going through the Advanced Search engine. The Advanced Search has a few parameters that are passed in the URL for a search query:

• all these words: the operator passed is as_q like this.

<input class="" type="text" name="as_q"> 

• this exact word or phrase: the operator passed is as_epq
• any of these words: the operator passed is as_oq
• none of these words: the operator passed is as_eq

So I named the HTML textboxes with the corresponding names and concatenated the above parameters to the search query.