SO Answer / Show or Hide the visibility of specific div with two links

See http://stackoverflow.com/questions/14099510/show-or-hide-the-visibility-of-specific-div-with-two-links

by KooiInc MeHere

HTML

<button id="toggle">toggle</button> <span id="form">click button to toggle visibility</span>
<br>
<button id="toggle2">toggle2</button> <span id="form2">bonus: toggle visibility using opacity/css</span>

CSS

#form2 {
    opacity: 1; 
    background: #fff;
    -webkit-transition: opacity linear 1s;
    -moz--transition: opacity linear 1s;
    -transition: opacity linear 1s;
}
#form2.hide {
    opacity: 0;
    -webkit-transition: opacity linear 1s;
    -moz--transition: opacity linear 1s;
    -transition: opacity linear 1s;
}

JavaScript

document.querySelector('#toggle').onclick = showHide;
document.querySelector('#toggle2').onclick = function(){
    var el = document.querySelector('#form2');
    el.className = el.className.length ? '' : 'hide';
};

function showHide(){
    var toggleStyle = document.querySelector('#form').style;
    toggleStyle.display = toggleStyle.display ? '' : 'none';
}