System for supporting Web applications on a point-of-sale, POS, terminal, the system comprising: a client apparatus configured to connect the POS terminal to a network using a plurality of communication protocols and transaction protocols, transaction protocols including HTTP, ISO8583 and XML operations; the client apparatus including at least one customized WML and Script extension added to preexisting WAP standards to form an application development and runtime environment for developing applications for download and use on the POS terminal, the client apparatus arranged to: download, run, and update applications from application servers connected to the network using HTTP on top of TCP/IP; enable one or more applications to use multiple communication protocols when connected to distinct access networks; extend a web based runtime environment to perform electronic ISO8583 operations using POS peripheral devices, the web based runtime environment configured to support persistence of information and to prevent multi-application interference by supporting multi-applications independently carried out in distinct virtual execution environments; and recognize, access, and control a plurality of POS peripheral devices, the POS peripheral devices comprising input and output peripheral devices, wherein the system further comprises: transaction servers configured to be accessed by the client system for executing electronic operations using different transaction protocols. a client apparatus configured to connect the POS terminal to a network using a plurality of communication protocols and transaction protocols, transaction protocols including HTTP, ISO8583 and XML operations; the client apparatus including at least one customized WML and Script extension added to preexisting WAP standards to form an application development and runtime environment for developing applications for download and use on the POS terminal, the client apparatus arranged to: download, run, and update applications from application servers connected to the network using HTTP on top of TCP/IP; enable one or more applications to use multiple communication protocols when connected to distinct access networks; extend a web based runtime environment to perform electronic ISO8583 operations using POS peripheral devices, the web based runtime environment configured to support persistence of information and to prevent multi-application interference by supporting multi-applications independently carried out in distinct virtual execution environments; and recognize, access, and control a plurality of POS peripheral devices, the POS peripheral devices comprising input and output peripheral devices, download, run, and update applications from application servers connected to the network using HTTP on top of TCP/IP; enable one or more applications to use multiple communication protocols when connected to distinct access networks; extend a web based runtime environment to perform electronic ISO8583 operations using POS peripheral devices, the web based runtime environment configured to support persistence of information and to prevent multi-application interference by supporting multi-applications independently carried out in distinct virtual execution environments; and recognize, access, and control a plurality of POS peripheral devices, the POS peripheral devices comprising input and output peripheral devices, wherein the system further comprises: transaction servers configured to be accessed by the client system for executing electronic operations using different transaction protocols.