JSFiddle - React, Tailwind, and code Playground

HTML

<aside id="like">
    <img onclick="_like()" src="http://img2.wikia.nocookie.net/__cb20120118234601/callofduty/images/c/cf/Facebook_like_buton.png" alt="J'aime"/>
    <img onclick="_dislike()" src="http://www.hiremedia.uk/dev/wp-content/uploads/2015/01/Facebook-dislike-png.png" alt="Je N'aime Pas"/>
    <input id="ilosc" readonly="readonly" value="5891" />
</aside>

CSS

#like {
    text-align: center;
}

#like img {
    max-width: 50px;
    max-height: 50px;
}

#like img:hover {
    transform: scale(1.1);   
}

#like input {
    display: block;
    margin: 5px auto;
}

input {
    border: 0;
    text-align: center;
    font-weigh: bold;
    font-size: 2em;
    padding: 0;
    background-color: #FFF;
}

JavaScript

_val = document.getElementById('ilosc').value;
_klikniete = false;

function _like() {
    if(!_klikniete) {
        _val = document.getElementById('ilosc').value;
        document.getElementById('ilosc').value = parseInt(_val) + 1;
        _klikniete = true;
    }
    else
        alert("Déjà vous avez donné voix!");
}

function _dislike() {
    if(!_klikniete) {
        _val = document.getElementById('ilosc').value;
        document.getElementById('ilosc').value = parseInt(_val) - 1;
        _klikniete = true;
    }
    else
        alert("Déjà vous avez donné voix!");
}