scroll.js

//note:offset & speed could be setup as globals

/** 
on page load or ajax update:
if(window.location.hash) {
    // Fragment exists
   scroll(window.location.hash,100,500);
}

direct:
scroll('#id3',100,750)
*/

function scroll(anchor,offset,speed){
  $('html, body').animate({ // animate both for cross browser support
    scrollTop:$(anchor).position().top - offset
  }, speed);
}

// Scroll down to content
$('a.anchor-click').click( function(evt) {
    evt.preventDefault();
    scroll('#id3',100,750);
});