How to eliminate the extra blank space at the bottom of the created web page when browsing

When using Dreamweaver or FrontPage to create HTML web pages, we may encounter this problem: once a good web page in the software is placed in a browser, more or less blank space will inexplicably appear at the bottom of the web page. So how do we eliminate this gap?
At first I thought that I just needed to add a CSS to the web page code to constrain the height of the web page, but it turns out that this doesn't work.

reason:

First of all, we need to know that when using software to write web pages, most of the time they are "stacked" through a graphical interface. When stacking web pages in this way, when creating layers or tables, the height defined by the software for the layers or tables will often exceed the height we want, but this is not visible in the software; however, when we open the web page in a browser, we will find that the blank spaces that do not exist in the software will be displayed in the browser.

The height of a web page cannot be constrained simply by adding an html{height:XX px;} because in a web page, the characteristics of other elements nested inside an element have a higher priority. For example: If you have the following code in the same web page: body{font-size: 10px;} p {font-size: 9px;}, then the font size in the <p> element of the web page should be 9px instead of 10px. Due to the existence of this rule, when the total height of the middle layer of a web page is greater than the value of XX in html{height:XX px;}, html{height:XX px;} will naturally have no effect.

Solution:

For web page codes written by software like this, unnecessary blank spaces can be removed from the web page by looking for the definition of layer or table height in CSS and then modifying the height value.