javascript - Specific number validation? -

is possible validate field specific set of numbers using javascript? example in postcode field can enter 4 numbers be accepted e.g. 2747,2750, 2753, 2760, 2777. other number returned false. have done bit of searching around can't seem find of use specific situation , i'm quite knew javascript sort of great.

should simple:

live demo

1. create list of numbers
2. create object every number key , whatever property.
3. if come server, send , parse them json.// skip
4. in js, var validnumbers = json.parse(serverresponse); // skip
5. use object, not array. array.prototype.indexof slower , needs polyfill.
6. object property access o(1) , universally supported.
7. your object looks this: var validnumbers = {"2747": "2747", etc..}
8. get input user.
9. if (typeof validnumbers[userinput] !== undefined) {//valid} else {//invalid}