JSFiddle - React, Tailwind, and code Playground

HTML

<a href='#'>fds</a>

JavaScript

var shiftDown = false;
this.onkeydown = function(evt){
    var evt2 = evt||window.event;
    var keyCode = evt2.keyCode || evt2.which;
    if(keyCode==16)shiftDown = true;
};
this.onkeyup = function(){
    shiftDown = false;
};
this.onload = function(){
    elements = document.getElementsByTagName('A');
    for(var i in elements)
        elements[i].onclick = function(){
            alert(shiftDown);
            return false;
        }    
}