JSFiddle - React, Tailwind, and code Playground

by oms02

HTML

<input type="text" id="texto"/>

CSS

#texto{float:left;}
#contador{float:left;clear:both;}

JavaScript

jQuery.fn.repeticiones = function(){

$(this).each(function(){
	var input = $(this);
	var contador = $("<span id='contador'></span>");
	input.after(contador);

	input.keyup(function(e){
		input = $(this);
		var clave = input.attr('value');

		function repCarac(p){
			var carac, expr;
			var coinc;
			var coincacum = '';
			var numcoinc = 0;
			for(var i=0;i<p.length;i++){
				carac = p.charAt(i);
				expr = new RegExp(carac,'g');
				coinc = p.match(expr);
				if(coinc.length > 1){
					if(coincacum.match(expr))
						{continue;}
					else{
						coincacum = coincacum + carac;
						numcoinc = numcoinc + coinc.length;
					}
				}
			}
			return numcoinc;
		}
		contador.text('coincidencias: '+repCarac(clave));

	});
});
}

$(document).ready(function(){
   $("#texto").repeticiones();
});