Set callback context for setTimeout() and setInterval()

By default, the context (this) for window.setTimeout() callbacks is set to the global object (window in browsers).

When working with classes, you sometimes need to keep the context to be that of the class instance. You can achieve this using the bind() method to explicitly set the context.

function UselessDelay()
{
    this.message='Why was I delayed?';
}

UselessDelay.prototype.start=function()
{
    window.setTimeout(this.show.bind(this),1000);
}

UselessDelay.prototype.show=function()
{
    console.log(this.message);
};

Usage

var ud=new UselessDelay();
ud.start();//Will show 'Why was I delayed?' after 1 second