When you want to compile your GWT module for only specific browser, you can change UserAgent.gwt.xml inside gwt-user.jar in package com.google.gwt.user. Find this text and change it as you wish: <define-property name="user.agent" values="ie6,gecko,gecko1_8,safari,opera"> gecko - Mozilla ,gecko1_8 - FireFox I want to compile for only IE , then I change it into <define-property name="user.agent" val