I found this regular expression for Arabic letters but it is also allowing numbers with letters. How can I change it to let it allow letters only ?
/[\\u0600-\\u
Probably you'd have to check what range the numbers match and exclude it (formally not include in brackets expression).
Here I've found another helpful source.
I'd suggest this for only letters
/[\u0600-\u065F\u066A-\u06EF\u06FA-\u06FF]/
as this matches arabic digits only
/[\u0660-\u0669\u06F0-\u06F9]/
Edit:
I've found that there are two ranges for arabic and arabic-indic digits in unicode.
If you need a regex to match a line just then, when it contains arabic letters and numbers - use this:
/^[\u0600-\u06FF]*$/
If you want to also discourage arabic digits - use this:
/^[\u0600-\u065F\u066A-\u06EF\u06FA-\u06FF]*$/
If you want to match a substring, not only a whole line, use this:
/\b[\s\u0600-\u065F\u066A-\u06EF\u06FA-\u06FF]*\b/