qooxdoo

qx.Class.define("custom.Application",
{
  extend : qx.application.Standalone,

  members :
  {
    main : function()
    {
      this.base(arguments);

      // Create button
      var button1 = new qx.ui.form.Button("First Button", 
                                          "icon/22/apps/internet-web-browser.png");

      // Document is the application root
      var doc = this.getRoot();

      // Add button to document at fixed coordinates
      doc.add(button1, {left: 100, top: 50});

      // Attach a tooltip
      button1.setToolTip(new qx.ui.tooltip.ToolTip("A nice tooltip",
                                                   "icon/32/status/dialog-information.png"));

      // Add an event listener
      button1.addListener("execute", function(e) {
        alert("Hello World!");
      });
    }
  }
});