manipulating visibility using js
function toggleClock() {
// get the clock
var myClock = document.getElementById('clock');
// get the current value of the clock's display property
var displaySetting = myClock.style.display;
// also get the clock button, so we can change what it says
var clockButton = document.getElementById('clockButton');
// now toggle the clock and the button text, depending on current state
if (displaySetting == 'block') {
// clock is visible. hide it
myClock.style.display = 'none';
// change button text
clockButton.innerHTML = 'Show clock';
}
else {
// clock is hidden. show it
myClock.style.display = 'block';
// change button text
clockButton.innerHTML = 'Hide clock';
}
}