1. A method for reliable mashup, comprising the steps of: intercepting, by an intercepting module, a data update request submitted by a client browser to at least one of a plurality of services providing mashup page data before said request arrives at said at least one service, wherein said client browser is in a client computer; performing consistency validation on said request by a consistency validator using consistency rules to produce a validity determination; and forwarding, by a forwarding module, said request from said consistency validator to said at least one service in response to said validity determination.