e. 0 false, but 0 ! false), to check for the presence of value within array, you need to check if its not equal to (or greater than) -1. It is not necessary to have key name in the array. At same time I need to check for this to display the error if the array possesses the key name.No need of JQuery simply you can do.as with any value for email will return you true, if there is no such property or that property value is null or "invPrice" : "353.85" ] Is there a way I can check if a new localProductCode already exists in the localValues array? Thank you.