function highlight_nav(doc_id){if(doc_id==1){$('#link1 a').css('background','url(/images/home.jpg)  0 35px');}
if(doc_id==2){$('#link2 a').css('background','url(/images/about_us.jpg) repeat 0 35px');}
if(doc_id==3){$('#link3 a').css('background','url(/images/buying_bullion.jpg) repeat 0 35px');}
if(doc_id==4){$('#link4 a').css('background','url(/images/storing_your_bullion.jpg) repeat 0 35px');}
if(doc_id==5){$('#link5 a').css('background','url(/images/contact_us.jpg) repeat 0 35px');}}