kindly see the visibility sample up here ,
in the first rows of the javascript , they declared some variables , but i couldnt understand why they declared a variable named toggle with no value or type.

// Get references to page elements and create a link dynamically
    var intro = document.getElementById('intro'),
        dets = document.getElementById('details'),
        a = document.createElement('a'),
        toggle; <- here i cant figure why they declared toggle ... !!!

the whole example in jsfiddle is an example showing how we can use the visibility css proporty.....


forget the first question i understand now why they declared the toggle variable.....
but now i cant understand why they populated the anchor this way :
a.appendChild(document.createTextNode('Hide details'));
why not this way with the innerHTML method ???!!!
a.innerHTML = 'View details';

It's easier to follow what they did in code. They easily could have made the entire anchor tag with innerHTML, but chose to be explicit for the sake of readability.