To speed things up and conserve bandwidth, browsers attempt to keep local copies of pages, images, and other content you’ve visited, so that it need not be downloaded again later. Occasionally this caching scheme goes awry (e.g. the browser insists on showing out-of-date content) making it necessary to bypass the cache, thus forcing your browser to re-download a web page’s complete, up-to-date content. This is sometimes referred to as a “hard refresh”, “cache refresh”, or “uncached reload”. The rest of your cache is not affected.
How to Bypass your Cache
In most Windows and Linux browsers
Link text down Ctrl and press F5.
In Apple Safari
Hold down ⇧ Shift and click the Reload toolbar button.
In Chrome and Firefox for Mac