Template:Team:NCTU Formosa/js

/* Smooth scrolling

  Changes links that link to other parts of this page to scroll
  smoothly to those links rather than jump to them directly, which
  can be a little disorienting.
  
  sil, http://www.kryogenix.org/
  
  v1.0 2003-11-11
  v1.1 2005-06-16 wrap it up in an object

• /

var ss = {

 fixAllLinks: function() {
   // Get a list of all links in the page
   var allLinks = document.getElementsByTagName('a');
   // Walk through the list
   for (var i=0;i<allLinks.length;i++) {
     var lnk = allLinks[i];
     if ((lnk.href && lnk.href.indexOf('#') != -1) && 
         ( (lnk.pathname == location.pathname) ||

('/'+lnk.pathname == location.pathname) ) &&

         (lnk.search == location.search)) {
       // If the link is internal to the page (begins in #)
       // then attach the smoothScroll function as an onclick
       // event handler
       ss.addEvent(lnk,'click',ss.smoothScroll);
     }
   }
 },

 smoothScroll: function(e) {
   // This is an event handler; get the clicked on element,
   // in a cross-browser fashion
   if (window.event) {
     target = window.event.srcElement;
   } else if (e) {
     target = e.target;
   } else return;

   // Make sure that the target is an element, not a text node
   // within an element
   if (target.nodeName.toLowerCase() != 'a') {
     target = target.parentNode;
   }
 
   // Paranoia; check this is an A tag
   if (target.nodeName.toLowerCase() != 'a') return;
 
   // Find the <a name> tag corresponding to this href
   // First strip off the hash (first character)
   anchor = target.hash.substr(1);
   // Now loop all A tags until we find one with that name
   var allLinks = document.getElementsByTagName('a');
   var destinationLink = null;
   for (var i=0;i<allLinks.length;i++) {
     var lnk = allLinks[i];
     if (lnk.name && (lnk.name == anchor)) {
       destinationLink = lnk;
       break;
     }
   }
   if (!destinationLink) destinationLink = document.getElementById(anchor);

   // If we didn't find a destination, give up and let the browser do
   // its thing
   if (!destinationLink) return true;
 
   // Find the destination's position
   var destx = destinationLink.offsetLeft; 
   var desty = destinationLink.offsetTop;
   var thisNode = destinationLink;
   while (thisNode.offsetParent && 
         (thisNode.offsetParent != document.body)) {
     thisNode = thisNode.offsetParent;
     destx += thisNode.offsetLeft;
     desty += thisNode.offsetTop;
   }
 
   // Stop any current scrolling
   clearInterval(ss.INTERVAL);
 
   cypos = ss.getCurrentYPos();
 
   ss_stepsize = parseInt((desty-cypos)/ss.STEPS);
   ss.INTERVAL =

setInterval('ss.scrollWindow('+ss_stepsize+','+desty+',"'+anchor+'")',10);

   // And stop the actual click happening
   if (window.event) {
     window.event.cancelBubble = true;
     window.event.returnValue = false;
   }
   if (e && e.preventDefault && e.stopPropagation) {
     e.preventDefault();
     e.stopPropagation();
   }
 },

 scrollWindow: function(scramount,dest,anchor) {
   wascypos = ss.getCurrentYPos();
   isAbove = (wascypos < dest);
   window.scrollTo(0,wascypos + scramount);
   iscypos = ss.getCurrentYPos();
   isAboveNow = (iscypos < dest);
   if ((isAbove != isAboveNow) || (wascypos == iscypos)) {
     // if we've just scrolled past the destination, or
     // we haven't moved from the last scroll (i.e., we're at the
     // bottom of the page) then scroll exactly to the link
     window.scrollTo(0,dest);
     // cancel the repeating timer
     clearInterval(ss.INTERVAL);
     // and jump to the link directly so the URL's right
     location.hash = anchor;
   }
 },

 getCurrentYPos: function() {
   if (document.body && document.body.scrollTop)
     return document.body.scrollTop;
   if (document.documentElement && document.documentElement.scrollTop)
     return document.documentElement.scrollTop;
   if (window.pageYOffset)
     return window.pageYOffset;
   return 0;
 },

 addEvent: function(elm, evType, fn, useCapture) {
   // addEvent and removeEvent
   // cross-browser event handling for IE5+,  NS6 and Mozilla
   // By Scott Andrew
   if (elm.addEventListener){
     elm.addEventListener(evType, fn, useCapture);
     return true;
   } else if (elm.attachEvent){
     var r = elm.attachEvent("on"+evType, fn);
     return r;
   } else {
     alert("Handler could not be removed");
   }
 } 

}

ss.STEPS = 25;