$(document).ready(function(){

    $('.contador').maxlength({
    maxCharacters: 300, // Characters limit
    status: true, // True to show status indicator bewlow the element
    statusClass: "contador", // The class on the status div
    statusText: " Caracteres restantes.", // The status text
    notificationClass: "notification", // Will be added when maxlength is reached
    showAlert: false, // True to show a regular alert message
    alertText: "You have typed too many characters.", // Text in alert message
    slider: true // True Use counter slider
    });
});