Javascript not reloading after postback?

I have a web page that contains the "FullCalendar" control that's written in javascript/jQuery. When a user clicks on a day, a form pops up (this form is just a <div> container with textboxes and labels). In this popup form, their is a label control that contains a default message. This label also will display any error messages when and if they occur. Let's say a user clicks the submit button, this will save a record to the database causing any potential errors. In this case...an error does occur and is correctly displayed in the label cotnrol. However, when I go click the cancel button, which is just an HTML <input> control, the "onclick" executes a javascript function that will reload the "default" message. Herein lies the problem. The default message doesn't appear rather the previous message. Not sure what I'm doing wrong or need to do?

Thanks,