/**
 * @author A List Apart
 * @see http://www.alistapart.com/articles/makingcompactformsmoreaccessible
 */
function initOverLabels()
{
    if (!document.getElementById) 
        return;
    
    var labels, id, field;
    
    // Set focus and blur handlers to hide and show 
    // labels with 'overlabel' class names.
    labels = document.getElementsByTagName('label');
    for (var i = 0; i < labels.length; i++)
	{
        if (labels[i].className == 'overlabel')
		{
            // Skip labels that do not have a named association
            // with another field.
            id = labels[i].htmlFor || labels[i].getAttribute('for');
            if (!id || !(field = document.getElementById(id)))
			   continue;
            
            // Change the applied class to hover the label 
            // over the form field.
            labels[i].className = 'overlabel-apply';
            
            // Hide any fields having an initial value.
            if (field.value !== '')
                hideLabel(field.getAttribute('id'), true);
            
			// Set handlers to show and hide labels.
            field.onfocus = function(){
                hideLabel(this.getAttribute('id'), true);
            };
            field.onblur = function(){
                if (this.value === '')
                    hideLabel(this.getAttribute('id'), false);
            };
            
            // Handle clicks to label elements (for Safari).
            labels[i].onclick = function(){
                var id, field;
                id = this.getAttribute('for');
                if (id && (field = document.getElementById(id)))
                    field.focus();
            };
            
        }
    }
};

function hideLabel(field_id, hide){
    var field_for;
    var labels = document.getElementsByTagName('label');
    for (var i = 0; i < labels.length; i++) {
        field_for = labels[i].htmlFor || labels[i].getAttribute('for');
        if (field_for == field_id) {
            labels[i].style.textIndent = (hide) ? '-1000px' : '0px';
            return true;
        }
    }
}

window.addEvent('domready', function()
{
	initOverLabels();
});