How to prevent the entire page from reloading?

Good day.

I am creating a theme for Drupal 7, and everything seems to be going well so far. A couple of questions have arisen.

A bit about my theme.

There is a main menu in the primary_link region (where the content type is selected) (and in the header region)

there is a navigation menu for articles of a specific type, which changes based on the main menu. (in the left_column region) and (in the main-wrapper region)

and there is a content column where specific content types are displayed depending on the main menu.  (in the right_column region) and (in the main-wrapper region)

The first question. 

How can I make it so that when selecting in the primary link, only the region below in the structure reloads? Accordingly,  the main-wrapper region

then when selecting in the left_column region, only the right_column region reloads.

I understand that I need to use AJAX here, but I haven't found anything clear on this topic.

The second question

How can I make it so that a specific content type is displayed in the left column? (a special view - form) The lists are different for each item in the main menu and accordingly in the right column depending on the selected element in the left column.

The third question

I made three columns and they are of different heights. I want them to be the same height. I am using Div for formatting.

In page.tpl.php I am using Drupal 7

the following piece of code

<script language="JavaScript" type="text/javascript">

	function setEqualHeight(columns){
		var tallestcolumn = 0;
		columns.each(function(){
			currentHeight = $(this).height();
			if(currentHeight > tallestcolumn){
				tallestcolumn = currentHeight;
				}
			}
		);
		columns.height(tallestcolumn);
	}
	$(document).ready(function() {
		setEqualHeight($(".container > div"));

});

</script>

Finally figured out this hassle after dinner :) It turns out in Drupal 7, it doesn't like when you write $

it needs to be replaced with jQuery and everything worked immediately with just a click.

As I read, the reason is that jQuery works in noConflict mode 

it should look something like this: 

jQuery(document).ready(function() {
setEqualHeight(jQuery(".container > div"));
});

So everywhere replace $ with jQuery and happiness will come to you. 

I hope this information will be useful to someone.

The first two questions remain open.