# Set one tag value to another tag's value on valueChanged event **URL:** \ **Category:** Ignition\ **Tags:** ignition81, perspective, scripting\ **Created:** [July 20, 2023, 8:35pm UTC](https://forum.inductiveautomation.com/t/set-one-tag-value-to-another-tags-value-on-valuechanged-event/76682 "2023-07-20T20:35:17Z")\ **Posts on this page:** 1\ **Showing post:** 6
**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\ **Post date:** [July 20, 2023, 9:46pm UTC](https://forum.inductiveautomation.com/t/set-one-tag-value-to-another-tags-value-on-valuechanged-event/76682/6 "2023-07-20T21:46:38Z")
In a script, you can not directly address a value. This: `'[.]Online'` is just a string. Technically, `system.tag.read()` will work but it's deprecated. There are two other functions you can use to read tag values depending on if you need it to block or not. `system.tag.readBlocking()` `system.tag.readAsync()` And they return a `List` of `qualifiedValues` so you must index into them as such and access the value property. This post will give you a quick history lesson on this, if you're interested. > [@Python List Comprehensions Help](https://forum.inductiveautomation.com/t/python-list-comprehensions-help/56621/43): > > I think I can help clarify this a little, although, this is just my outsider understanding of the issue and why I think the change was a good one. In 7.9 there were 6 functions that worked with the tag system system.tag.read() system.tag.readAll() system.tag.write() system.tag.writeAll() system.tag.writeSyncronous() system.tag.writeAllSyncronous() This was confusing for some users who expected similarly named functions to behave the same. For instance, system.tag.write() is an \*asynchronou… --- _[View the full topic](https://forum.inductiveautomation.com/t/set-one-tag-value-to-another-tags-value-on-valuechanged-event/76682)._