web services are open standard based web application that interact with other data in terms of exchange data, for example we make ab application then web services can convert it on web application.Web services are XML based information exchange system that uses internet for application to application interaction.
Component of web services:
1.SOAP(Simple object access protocol):-it uses for transfer message
2.UDDI(Universal description discovery and integration)
3.WSDL(Web service description language):describe the availability of services
you can use different platform(programming) based application and access via different programming based platform due to web services.