function writeDate() {
  var today = new Date();
  var year = today.getFullYear();
  document.write(year);
}

$(document).ready(function(){
  $(".roll").bind("mouseover",rollover);
  $(".roll").bind("mouseout",rollout);
});

function rollover() {
  var path =  this.src.substr(0,this.src.lastIndexOf("."));
  var filetype = this.src.substr(this.src.lastIndexOf("."));
  this.src = path + "_over" + filetype;
}

function rollout() {
  var path =  this.src.substr(0,this.src.lastIndexOf(".")-5);
  var filetype = this.src.substr(this.src.lastIndexOf("."));
  this.src = path + filetype;
}