与CSS伪选择器一起使用'this'关键字

Question

I want to use pseudo selectors along with this attribute. How can I use it.

$('input:valid').length

It will return 1 if its valid else 0 for invalid.

the same if I want to achieve using this how can I do that. something like this.

$('input').focusout(function(){
var flag=$('this:valid').length;
console.log(flag);
})

But its not working. Please guide me how to do this.

Answer 1

您应该使用is（） ：

var flag = $(this).is(':valid'); //returns boolean

Answer 2

Try this instead:

var flag=$(this).filter(':valid').length

REF: .filter() | jQuery API Documentation