/* ---------------------------------
checks that a user has entered data to serach on
If not, stops form submission and inserts error message into page as per site style
--------------------------------- */
function checkSearchString(e) {		
	var searchbox = document.getElementById('schRes');
	var searchform = document.getElementById('searchform');
	
	if (!searchbox || !searchform) {
		return;
	}
			
	if (searchbox.value.length == 0) {
		if (!document.getElementById('errormessage')){
			searchform.parentNode.innerHTML = generateErrorHtml() + searchform.parentNode.innerHTML;
		}
		// prevent form submission
		YAHOO.util.Event.preventDefault(e);
	}
}

function generateErrorHtml() {
	var html = '';
	
	html += '<div class="greyBox error" id="errormessage">';
	html += '<p>Missing Details</p>';
	html += '<ul>';
	html += '<li>Keywords</li>';
	html += '</ul>';
	html += '</div>';

	return html;
}


window.onload = function() {
	MM_preloadImages('/images/functionbuttons/pagetoproll.gif','/images/functionbuttons/printablepagerollover.gif','/images/functionbuttons/findbuttonrollover.gif');

	formToCheck = document.getElementById('searchform');
	if (formToCheck) {
		YAHOO.util.Event.addListener(formToCheck, 'submit', checkSearchString);
	}
	
	// find button rollovers
	findbuttons = YAHOO.util.Dom.getElementsByClassName('findbutton', 'input');
	if (findbuttons && findbuttons.length > 0) {
		YAHOO.util.Event.addListener(findbuttons, 'mouseover', function() {
			this.src = '/images/findbuttonrollover.gif';
		});
		
		YAHOO.util.Event.addListener(findbuttons, 'mouseout', function() {
			this.src = '/images/findbutton.gif';
		});
	}
	
	// 'new search' buttons
	nsbuttons = YAHOO.util.Dom.getElementsByClassName('newsearch', 'a');
	if(nsbuttons && nsbuttons.length > 0) {
		YAHOO.util.Event.addListener(nsbuttons, 'mouseover', function() {
			this.firstChild.src = '/images/functionbuttons/newsearchrollover.gif';
		});

		YAHOO.util.Event.addListener(nsbuttons, 'mouseout', function() {
			this.firstChild.src = '/images/functionbuttons/newsearch.gif';
		});
	}
}