You can simply add validate class for validation in magento 1.
For Phone Number Validation
'validate-phoneStrict' => 'Please enter a valid phone number. For example (123) 456-7890 or 123-456-7890.'
'validate-phoneLax' => 'Please enter a valid phone number. For example (123) 456-7890 or 123-456-7890.'
'validate-fax' => 'Please enter a valid fax number. For example (123) 456-7890 or 123-456-7890.'
For Zip Code Validation
'validate-zip' => 'Please enter a valid zip code. For example 90602 or 90602-1234.'
'validate-zip-international' => 'Please enter a valid zip code.'