// jQuery for Drupal 7 [BEGIN]
(function ($) {
// [jQuery BEGIN] début des fonctions
$(document).ready(function() {
    var std_url;
 $('.tc_front_img img').hover( function(){
     std_url = $(this).attr('src');
     var url =std_url;
   //  console.log(url);
     url = url.replace(/service_medium_accueil/g, "service_hover");
     //url =  url.replace(/\.(jpg|gif|png)$/, '_hover$&')
     //console.log(url);
     if(UrlExists(url)){
         $(this).attr('src', url);
     }
 },
 function(){
     $(this).attr('src', std_url);
 } 
);
 
function UrlExists(url)
{
  var http = new XMLHttpRequest();
  http.open('HEAD', url, false);
  http.send();
  return http.status!=404;
}
// [jQuery END] fin des fonctions
});
// jQuery for Drupal 7 [END]
}(jQuery));