javascript open a function which is a value of a funtion

I want the value of this :
document.getElementById('clearthisok').value;
to be referred to a function knowing that I don’t know its value.

Ex:

<script>
document.getElementById('clearthisok').value="xxx01();";

//syntax that open the function xxx01()//

function xxx01()
{
Alert("it’s working")
}
</script>

 

You can use eval()

 

eval(document.getElementById('clearthisok').value)