Again, the issue results when a user adds an item to the cart and nothing appears to happen until the page is refreshed. Upon refreshing the browser, the cart would then reflect the items. This occurs when the Display modal popup upon 'Add to cart", check box is selected in the Virtuemart Configuration's checkout tab. Enabling this setting is required to use the AJAX cart. However, the issue persisted even having the Display modal popup upon 'Add to cart" check as it should be.
We found this very troubling that all of the sudden the shopping cart mechanism would stop working. After much research and testing, we discovered that the cart pop up was displaying because of conflicts with jQuery. We stumbled upon many solutions but found the quickest and most effective solution to be the installation of a plugin: jQuery Easy.
This plugin is meant to help clean and resolve front and back end issues when using instances of jQuery alongside the Mootools libraries. All you have to do is install and enable this plugin: jQuery Easy.
If you require any further assistance, feel free to contact AdverGroup Web Design!