RegExp help in validating numbers in a string field

[Suryansh Verma]

Hello Community,

I have a string field for inputting hours.

The field should only allow negative numbers & decimal(.) & also comma(,) for that i am using the below expression.

/^-?(?:\d+|\d{1,3}(?:,\d{3})+)(?:(\.|,)\d+)?$/

now I also want to restrict the decimal places (before and after ) to upto 3 digits only and also 

so accepted value should be 
-123.456 or -123,456 and not -1234.5678 or -1234,5678

[Hemant Goldar]

@Suryansh Verma here is the regular expression - ^-?\d{1,10}([,.]\d{1,3})?$

[Suryansh Verma]

@Hemant Goldar Perfect !!!
Thanks for your help.