Mike, What I was trying to do was edit the last characer based upon a few conditions so that a show/hide function would work with and without javascript.
As well as the errors you spotted, when i was setting the href I was setting it to #calendar .nav, and not to #calendar #navleft. The addition of .text() on the end of .href() was just me trying things to see if they worked. Thankfully now, the script works. The whole thing now looks like this: $("#toggle").click(function(){ $("#calendar .arc").toggle(); $("#calendar .arc").Highlight(1000, '#ff9'); var $this = $(this); if($this.is ('.show')) { $this.removeClass('show'); $this.addClass('hide').empty().append('Show archived members'); var $ref = $("#calendar #navleft").attr("href"); $("#calendar #navleft").attr("href", $ref.slice(0, -1)+'0'); var $ref = $("#calendar #navright").attr("href"); $("#calendar #navright").attr("href", $ref.slice(0, -1)+'0'); } else { $this.removeClass('hide'); $this.addClass('show').empty().append('Hide archived members'); var $ref = $("#calendar #navleft").attr("href") $("#calendar #navleft").attr("href", $ref.slice(0, -1)+'1'); var $ref = $("#calendar #navright").attr("href") $("#calendar #navright").attr("href", $ref.slice(0, -1)+'1'); } return false; }); Many thanks again Mike :)