Write a function into Javascript that will toggle display a HTML element.

Answer:

function ShowHide(id)

        {

document.getElementById(id).style.display == '' ? document.getElementById(id).style.display = 'none' : document.getElementById(id).style.display = '';        

        }

We can call this function like
<a href="#" onclick="ShowHide('divid')">Show/Hide</a>

If the "divid" is already displaying on the page it will hide if not it will show on the page and so on.