Toggle default value of Text box

                    var t = document.getElementById('ID');
t.onfocus = hideText;
t.onblur = showText;

function hideText() {
	if(this.value == this.defaultValue) {
		this.value = '';
	}
}

function showText() {
	if(this.value == '') {
		this.value = this.defaultValue;
	}
}