JSFiddle - React, Tailwind, and code Playground

HTML

<div id="e1"></div>
    <div id="e2"></div>

CSS

#e1{
 width: 65%;   
}

#e2{
 width: 65px;   
}

JavaScript

jQuery( document ).ready( function(){
var e1 = jQuery( "#e1"), e2 = jQuery("#e2");
e1.html( getStyle( e1[0], "width" ) );
e2.html( getStyle( e2[0], "width" ) );
});



(function(){ 
var docElm = document.documentElement;
        matchesSelector = docElm.matchesSelector ||
                docElm.mozMatchesSelector ||
                docElm.webkitMatchesSelector ||
                docElm.msMatchesSelector ||
                docElm.oMatchesSelector;
        
        
    if( !matchesSelector ) {
    throw new Error( "no browser support");
    }
    
    function getStyle( element, style ) {
    var styleSheets = document.styleSheets,
        styleSheet, rule, rules, i,j,k,l,
        candidate, candidates = [], latestVal;
        
    l = styleSheets.length;
        
        for( i = 0; i < l; ++i ) {
        styleSheet = styleSheets[i];
        
        rules = styleSheet.cssRules || styleSheet.rules;
        
            if( !rules ) {
            continue;
            }
            
        k = rules.length;
        
            for( j = 0; j < k; ++j ) {
            rule = rules[j];
            
                if( matchesSelector.call( element, rule.selectorText ) ) {
                candidates.push( rule );
                }
            
            }
        }
        
    l = candidates.length;
    
        if( !l ) {
        return element.style[style];
        }
        
        for( i = 0; i < l; ++i ) {
        candidate = candidates[i];
        
            if( style in candidate.style ) {
            latestVal = candidate.style[style];
            }
        }
        
    
    return latestVal || element.style[style];
    }

window.getStyle = getStyle;
})();