Timezone field - JSM cloud

[SAI ABHIRAM CHUNDURU]

Hi All,

I am using a Jira service management project in which there is a customer portal with 5 to 6 forms populated with required custom fields.

One of the common custom fields is the single select - selection of  time zones which can be used to select while registering an incident. Currently there is a custom single select dropdown that has some of the manually entered options collected from some random website. 

Instead of this , is there any alternative way of implanting this in a dynamic manner which can list down all the available time zones and keeps updating itself with new zones or daylight savings changes etc. ?

Please suggest.

Thanks