Validar caducidad del sessionStorage

example.js

/**
* load the content via AJAX,
* and attempt to cache in sessionStorage
*/
(function() {
  
  var hasStorage = ("sessionStorage" in window && window.sessionStorage),
  storageKey = "yourUniqueStorageKey",
  now, expiration, data = false;
  
  try {
    if (hasStorage) {
      data = sessionStorage.getItem(storageKey);
      if (data) {
        // extract saved object from JSON encoded string
        data = JSON.parse(data);
        
        // calculate expiration time for content,
        // to force periodic refresh after 30 minutes
        now = new Date();
        expiration = new Date(data.timestamp);
        expiration.setMinutes(expiration.getMinutes() + 30);
        
        // ditch the content if too old
        if (now.getTime() > expiration.getTime()) {
          data = false;
          sessionStorage.removeItem(storageKey);
        }
      }
    }
  }
  catch (e) {
    data = false;
  }
  
  if (data) {
    // load data from session storage
    showContent(data.content);
  }
  else {
    // fallback to AJAX loader
    jQuery.ajax({
      type : "GET",
      url : your_ajax_url,
      dataType : "html",
      data : { action: "your-ajax-action" },
      success : function(content, status, xhr) {
        // save in session storage if available
        if (hasStorage) {
          try {
            sessionStorage.setItem(storageKey, JSON.stringify({
              timestamp: new Date(),
              content: content
            }));
          }
          catch (e) {
            // silently suppress, it doesn't really matter
          }
        }
        
        // show the new content
        showContent(content);
      }
    });
  }
})();

/**
* your function for displaying the content
* @param {String} content
*/
function showContent(content) {
  // your code here...
}