Sets or gets a progress bar's value.
Setting the value property sets the current value for the progress bar
and updates the displayed progress indication to reflect the progress as
a percentage of the targetValue.
The value property can be set to any number greater or equal to 0. Setting
value to a number greater than targetValue can be used to
indicate that a goal amount has been surpassed.
Getting the value property returns the current value.
Notes:
If a progress bar is connected to a dataset, setting the progress bar's value in code does not set the value of the connected field in the dataset.
To change the value in the connected dataset, set the field's value using
the setFieldValue() function.