var detached = false;

$(document).ready(function() {

  $(window).scroll(function() {
  
	if ( jQuery.browser.msie ) {
	    if($(window).scrollTop() > 440) {
			$('.left_navigation').css('position','absolute');
			$('.left_navigation').css('top',document.documentElement.scrollTop+'px');
		}
		else {
		  $('.left_navigation').css('position','relative');
		  $('.left_navigation').css('top','0px');
		}
	}
	else {
		if(!detached && $(window).scrollTop() > 440) {
		  $('.left_navigation').css('position','fixed');
		  $('.left_navigation').css('top','0px');
		  detached = true;
		}
		else if(detached && $(window).scrollTop() <= 440) {
		  $('.left_navigation').css('position','relative');
		  $('.left_navigation').css('top','0px');
		  detached = false;
		}      
	}
  });

});