obarveni textu

<script type="text/javascript">
  function change_color (e) {
    var x = document.getElementById("text").style.color = e;
  }
</script>

<div id="text"> Text </div>

<button onClick="change_color('green');">Zelená </button>
<button onClick="change_color('red')  ;">Červená</button>
<button onClick="change_color('gold') ;">Zlatá  </button>
<button onClick="change_color('black');">Černá  </button>

<script type="text/javascript">
  function change_color (e,f) {
    var x = document.getElementById(f).style.color = e;
  }
</script>

<div id="text"  > Text  </div>
<div id="text2" > Text2 </div>

<button onClick="change_color('green','text') ;">Zelená (Text)  </button>
<button onClick="change_color('red','text2')  ;">Červená (Text2)</button>

<span class='oi'>Ahoj</span> Ahoj <span class='oi'>Ahoj</span> Ahoj <span class='oi'>Ahoj</span> Ahoj

<script>
function styl(barva)  {
  document.getElementsByTagName("head")[0].innerHTML+= "<style>.oi {color: " + barva + "}</style>";
}

var barvy = ["red", "green", "blue"];

for (i = 0; i < barvy.length; i++)  {
  btn = document.createElement("button");
  btn.textContent = barvy[i];
  btn.onclick = function () {styl(this.textContent);};
  document.body.appendChild(btn);
}
</script>