Example of using timer in JavaScript_javascript tips

Copy code The code is as follows:

function foo()
{
}
setInterval( "foo()", 1000 );

If you use OO technology, you can do this,

Copy code The code is as follows:

// constructor
function MyObj
{
function foo()
{
alert( this.data );
}

this.timer = foo;
this.data = "Hello";

setInterval( "this.timer()", 1000 );
}

function Another()
{
// create timer when create object
var obj = new MyObj();

}

However, it doesn't work as you think. The reason is that the setInterval() function does not recognize the variable this. A workaround approach could be like this.

Copy code The code is as follows:

function Another()
{
var obj = nw MyObj();
setInterval( "obj.timer()", 1000 );
}

Obviously, it can work correctly, but if you are a perfectionist Otherwise, you won't be satisfied with it. Fortunately, you can put this action into the constructor, with a slight change in form.

Copy code The code is as follows:

// constructor
function MyObj
{
function foo()
{
alert( this.data );
}

this.timer = foo;
this.data = "Hello";

var self = this;
setInterval( function() { self.timer(); }, 1000 );
}

function Another()
{
var obj = new MyObj();

}

OK, by using a closure, that's it. As for the reasons, I want to leave it to the readers to think for themselves.

Finally, give an example of various test cases.

Copy code The code is as follows: