JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    Some text text text 
</div>

<div class="target">
    Target box with text
</div>

CSS

div{
    display: inline-block;
    margin: 20px;
    border: 1px solid;
    padding: 10px;
}

JavaScript

var inArticle = false;
		// The class you want to check:
		var parentClass = "target"; 

		function checkParent(e){
			if(e.parentElement && e.parentElement != $('body')){
				if ($(e).hasClass(parentClass)) {
					inArticle = true;
					return true;
				}else{
					checkParent(e.parentElement);
				}
			}else{
				return false;
			}
		}


		$(document).on('mouseup', function(){
			// Check if there is a selection
			if(window.getSelection().type != "None"){
				// Check if the selection is collapsed
				if (!window.getSelection().getRangeAt(0).collapsed) {
					inArticle = false;

					// Check if selection has parent
					if (window.getSelection().getRangeAt(0).commonAncestorContainer.parentElement) {
						// Pass the parent for checking
						checkParent(window.getSelection().getRangeAt(0).commonAncestorContainer.parentElement);
					};


					if (inArticle === true) {
						// If in element do something
						alert("You have selected something in the target element");
					}
				};
			}
		});