Access custom entity attributes using jscript soap or rest endpoint How ?

Hello Experts

I am not able to acccess  custom entity attributes using jscript soap or rest endpoint  . I got error the custom entity attribute(in my case new_active)

" value=No property 'new_active' exists in type 'Microsoft.Xrm.Sdk.Entity' at position 0."

can any one suggest  that is helpful

Thanks and regards

Muralikrishna