Question

How to assign indexes to variable names? For instance, project0, project1, project2, etc?

for (var i=0; i<data.length; i++)
{
    var project+i = new GanttProjectInfo(1, "Applet redesign", new Date(2010, 5, 11));
    var parentTask+i = new GanttTaskInfo(1, "Old code review", new Date(2010, 5, 11), 208, 50, "");
    project1.addTask(parentTask+i);
    // Load data structure        
    ganttChartControl.addProject(project+i);
    // Build control on the page
}

Answer 1

Just as @JaredFarrish suggested, you can simply use an array to store all the projects. Create them and add them to the array before the variable gets overwritten:

var projects = [];
for (var i = 0; i < data.length; i++) {
    var project = new GanttProjectInfo(1, "Applet redesign", new Date(2010, 5, 11));
    var parentTask = new GanttTaskInfo(1, "Old code review", new Date(2010, 5, 11), 208, 50, "");
    project.addTask(parentTask);
    ganttChartControl.addProject(project);

    // Push this project to the array to save it
    projects.push(project);
}

// Need to access the first project?
projects[0].foo();