<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>bootstrap3 &bootstrap4 in same html file</title>
</head>
<body>
<div class="bootstrap3">
some code here which require bootstrap3 css files
</div>
<div class="bootstrap4">
some code here which requires bootstrap4 css files
</div>
</body>
</html>
i have problem in this section so please help me out to solve this
I believe the quick answer is No, for a number of reasons.
Note, While I believe you're talking about CSS, you don't exactly state whether you're talking about the CSS of bootstrap or the JS of bootstrap, or both.
Regardless, surely both bootstrap 3 and 4 both have styles and JS functions with the same names, and would surely conflict - or just be overwritten. (The last thing loaded usually overwrites the previous thing loaded).
Secondly, a little comment here about cooperation.
The team should standardize on what to use, not go in different directions on something like this. ("Too many chefs in the kitchen" comes to mind.)
There should be a serious talk / debate (not argument ) about the pluses and minuses of which bootstrap to use. I acknowledge, that there are perfectly valid reasons not to use Bootstrap 4 (that's another story), but honestly - just because something is the latest thing, doesn't mean you HAVE to use it, and there are many more examples and "best practices" of Bootstrap 3 out there, at this point in time.
Regardless,I'd suggest that your team stay focused on solving the current problem at hand, IMHO.
It's not possible to integrate both bootstrap3 and bootstrap 4 because of many classes of the bootstrap library with the same name.
The best practice is to stick to particular bootstrap and use it Throughout your project. As the functionality of every bootstrap differs from one another, it is not a good practice to use different bootstraps for 1 project.
So I would suggest you to use Bootstrap based on your project needs like for e.g: whether you want to build mobile-responsive site first or web-responsive, come to conclusion and then decide which Bootstrap suits your needs.
