If you want to show/hide a div, you are on the right place here is an example
<input type=button value="Please click here" onClick="javascript:toggle()">
<script>
function toggle(){
var div1 = document.getElementById('welcomeform')
if (div1.style.display == 'none') {
div1.style.display = 'block'
} else {
div1.style.display = 'none'
}
}
</script>
<div id="welcomeform" style="display:none;">Welcome :-)</div>