/* ***************************************************************************************
 * File:             lindy_global.js
 * Description:      Global JavaScript utilities for Lindyfest
 * Revision History: 2005-11-13 [am] File created
 * **************************************************************************************** */

/* *************************************************************************
 * *************************************************************************
 * Global Constants & Variables 
 * *************************************************************************
 * ************************************************************************* */

/* Default page status - Typically does not work for Mozilla */
var gstrPAGE_STATUS = "Lindyfest 2006";

/* *************************************************************************
 * *************************************************************************
 * Global Functions
 * *************************************************************************
 * ************************************************************************* */
 
/* *****************************************
 * Function:    Init
 * Description: Initialization when page loads
 * Arguments:   None
 * Return:      None
 * ***************************************** */
function Init() {
   InitRollover();
   window.status = gstrPAGE_STATUS;
   return true;
}

/* *****************************************
 * Function:    InitRollover
 * Description: Init rollover images
 * Arguments:   None
 * Return:      None
 * ***************************************** */
function InitRollover() {
   /* Verify browser supports images */
   if(!document.getElementById) return;
   
	var imgOriginSrc;
	var imgTemp       = new Array();
	var imgArray      = document.getElementsByTagName('img');
	
	/* For each image in document, if hsrc element exists, it will be the rollover image */
   for(var i = 0; i < imgArray.length; i++) {
      /* src is normal image */
      imgTemp[i] = new Image();
      imgTemp[i].src = imgArray[i].getAttribute('src');
      
      /* hsrc attribute is rollover image */
      if(imgArray[i].getAttribute('hsrc')) {
         imgTemp[i] = new Image();
         imgTemp[i].src = imgArray[i].getAttribute('hsrc');
         
         /* rollover function */
         imgArray[i].onmouseover = function() {
            imgOriginSrc = this.getAttribute('src');
            this.setAttribute('src',this.getAttribute('hsrc'));
         }
         
         /* rollout function */
         imgArray[i].onmouseout = function() {
            this.setAttribute('src',imgOriginSrc);
         }
      }
   }
}
	
	var scrollInt;
	var scrTime, scrSt, scrDist, scrDur, scrInt;
	
	function replaceAnchorLinks()
	{
		var anchors, i, targ, targarr;
	
		if (!document.getElementById)
			return;
		
		// get all anchors
		anchors = document.getElementsByTagName("a");
		
		for (i=0;i<anchors.length;i++)
		{
		
			// check if href links to an anchor on this page
			if ( anchors[i].href.indexOf("#") != -1 && anchors[i].href.indexOf( document.URL ) != -1 )
			{
				// get name of target anchor
				targ = anchors[i].href.substring( anchors[i].href.indexOf("#")+1 );
				
				// find target anchor
				targarr = document.getElementsByName( targ );
				
				if (targarr.length)
				{
					anchors[i].className = (targarr[0].offsetTop < anchors[i].offsetTop) ? "up" : "down";
					anchors[i].id = "__" + targ;	// save target as id with prefix (used in onclick function below)
					anchors[i].onmousedown = function () { scrollToAnchor( this.id.substring( 2 ) ); return false; };
					anchors[i].href = "#";			// rewrite href
				}
			}
			
		}
	}
	
	
	/*
	SCROLL FUNCTIONS
	*/
	
	
	
	
	function scrollPage()
	{
		scrTime += scrInt;
		if (scrTime < scrDur) {
			window.scrollTo( 0, easeInOut(scrTime,scrSt,scrDist,scrDur) );
		}else{
			window.scrollTo( 0, scrSt+scrDist );
			clearInterval(scrollInt);
		}
	}
	
	function scrollToAnchor(aname)
	{
		var anchors, i, ele;
	
		if (!document.getElementById)
			return;
		
		// get anchor
		anchors = document.getElementsByTagName("a");
		for (i=0;i<anchors.length;i++) {
			if (anchors[i].name == aname) {
				ele = anchors[i];
				i = anchors.length;
			}
		}
		
		// set scroll target
		if (window.scrollY)
			scrSt = window.scrollY;
		else if (document.documentElement.scrollTop)
			scrSt = document.documentElement.scrollTop;
		else
			scrSt = document.body.scrollTop;

		
		
		scrDist = ele.offsetTop - scrSt;
		scrDur = 500;
		scrTime = 0;
		scrInt = 10;
		
		// set interval
		clearInterval(scrollInt);
		scrollInt = setInterval( scrollPage, scrInt );
	}
	
	
	
	
	/*
	EASING FUNCTIONS
	*/
	
	function easeInOut(t,b,c,d)
	{
		return c/2 * (1 - Math.cos(Math.PI*t/d)) + b;
	}
	

/* *************************************************************************
 * *************************************************************************
 * Main
 * *************************************************************************
 * ************************************************************************* */
onload=Init;