Coldfusion Sample Code

<cfset comparison = DateCompare("06/27/2013", Now(), "d")>
<cfoutput>
  <cfif comparison LTE 0>
    <img src="images/NEW_LOGO_NAME.png">
  <cfelse>
    <img src="images/OLD_LOGO_NAME.png">
  </cfif>
</cfoutput>
        

Javascript Sample Code

var logo = document.getElementById("logo");
if(new Date() >= new Date(2013, 5, 27, 0, 0, 0, 0)) {
  for(n in logo.attributes) {
    if(typeof logo.attributes[n] != "undefined" && typeof logo.attributes[n].name != "undefined" && logo.attributes[n].name == "src") {
      logo.attributes[n].value = "PATH_TO/NEW_LOGO.png";
    }
  }
}