I want to be able to check to see if a specific data attribute exists that starts with a specific value.

for example lets say i have the following HTML code:

 <div data-attr=123ABC></div>

 <div data-attr=123456><div>

 <div data-attr=TEST></div> 

and then i want to find any use of the data tag of data-attr that starts with 123

 if ($('[data-attr=123]').length > 0) { 

     //do something

 }

This appears to always return 0 as i have no data-attr=123 How would i make it so i can check for only that specific data attribute that starts with 123 and has anything after that?