As you may know, MSCRM uses htc files to format the different type of input fields as same as email address etc, see my another post.
If you want to get the value of an attribute, in CRM we use: DataValue, e.g: crmForm.all.new_number.DataValue;
Notice that the DataValue is the real data saved in the database.
However, if you want to get the formatted value, you may use this:
So the trick is give the DataValue overwrites the value property.
Put the following code into the entity's onLoad() event, and the same code puts into the field's onChange() event.
if(crmForm.all.new_number != null && crmForm.all.new_number.DataValue != null)
crmForm.all.new_number.value = crmForm.all.new_number.DataValue;