Change date on icon click event I'm trying to create a custom block that display the current date (Only Day of the month, 2 digits with leading zeros and A full textual representation of the day of the week) using the tocken module.

Now my problem is how to change the date when the next, prev icon is cicked?
For example: Today is saturday the 05th. When i click next, i get sunday the 6th. And when i click prev, i get friday the 04th. 
Maybe this can be possible using javascript or php.
There are two ways to go about this.
Pure JS
You can send the date shown to the JavaScript either via drupal_add_js or as a data attribute and let the JavaScript manage the date changes. You would need to change the current date +/- 1 when clicking on a button and figure out the name of the day and the day number of the day and display that. This should be relative simple to do.
AJAX
You can let the use AJAX and send the selected date to a custom menu callback which returns the markup for the new date.
Of the two solutions I would prefer the pure JS version. The Ajax version is more complex to implement and will generate a bigger load on the webserver. It could be a nice solution if you want to do advanced theming and don't want to place that logic in the JS (like weekends / holidays etc are displayed in different styles)