JAVASCRIPT XXXXX

    //READ FIELD VALUES
    <form onSubmit="checkAddress('email')" id="field">

    function checkAddress(email){
        var val = document.getElementById('field').value;
        if( val === ""){
            alert("Email required");
        }
    }

    //SETTING FIELD VALUES
    <form onBlur="fillCity()" id="zip">

    function fillCity(){
        var zipEntered = document.getElementById('field').value;
        document.getElementById('field').value = "Chicago"; //Se haria con un switch de varias ciudades pero se entiende
    }

    //READ AND SET PARAGRAPH TEXT
    <p onCick="fillCity()" id="textExtra">
    <form onCick="Expand()">
    function Expand(){
    document.getElementById('textExtra').innerHTML = "This is the full paragraph"