1. A method for providing a framework to develop a client application executed on multiple platforms, comprising steps of: (a) providing a framework acquiring information on platform independent user interface (UI) and information on business logic written by using a general-purpose programming language; (b) (i) generating a platform-dependent UI code, via a UI code generator, corresponding to the acquired information on the platform independent UI as UI code for a target platform among the multiple platforms and (ii) generating business logic code, via a logic code generator, corresponding to the acquired information on the business logic as business logic code for the target platform; and (c) generating a client application executable on the target platform by using the generated UI code and the generated business logic code, wherein the UI code generator including an elementary registry, a platform code generator, and a source code generator; wherein: (i) (A) the acquired UI information is delivered to the UI code generator, and the information is parsed and stored in the elementary registry, (B) the platform code generator reads the information stored in the elementary registry and generates UI code appropriate for a target platform, (C) and the source code generator converts the UI code appropriate for the target platform into a source code file for the target platform and then delivers the source code file to an application builder; (ii) (A) the acquired business logic information is parsed by a code analyzer of a logic code translator, wherein the logic code translator further including a preprocessor, a platform code translator, and a postprocessor, (B) the preprocessor performs code optimization tasks, (C) the platform code translator converts code processed by the preprocessor into logic code appropriate for the target platform and delivers the code to the postprocessor, (D) and the postprocessor converts the business logic code into a logic code file by performing additional tasks designated for the target platform and then delivers the logic code file to the application builder; (iii) the application builder compiles the acquired source code file and the logic code file to thereby generate a client application executable on the target platform.