Listing9-5.txt

var context = SP.ClientContext.get_current();
var list = context.get_web().get_lists().getByTitle('Test List');
var item = list.getItemById(2);
item.set_item('Title', 'New Title');
item.update();
context.executeQueryAsync(
    Function.createDelegate(this, function() {
        /* Do something when update succeeds */
    }),
    Function.createDelegate(this, function(s, args) {
        /* Do something when update fails */
    })
);