$(document).ready(function(){
lastBlock = $("#tab1");
maxWidth = 845; //210  - 700
minWidth = 50; //75 - 100


$("#a1").click(
function(){
$(lastBlock).animate({width: minWidth+"px"}, { queue:false, duration:400 });
$("#tab1").animate({width: maxWidth+"px"}, { queue:false, duration:400});
lastBlock = $("#tab1");
}
);

$("#a2").click(
function(){
$(lastBlock).animate({width: minWidth+"px"}, { queue:false, duration:400 });
$("#tab2").animate({width: maxWidth+"px"}, { queue:false, duration:400});
lastBlock = $("#tab2");
}
);

$("#a3").click(
function(){
$(lastBlock).animate({width: minWidth+"px"}, { queue:false, duration:400 });
$("#tab3").animate({width: maxWidth+"px"}, { queue:false, duration:400});
lastBlock = $("#tab3");
}
);

$("#a4").click(
function(){
$(lastBlock).animate({width: minWidth+"px"}, { queue:false, duration:400 });
$("#tab4").animate({width: maxWidth+"px"}, { queue:false, duration:400});
lastBlock = $("#tab4");
}
);


});