jquery selectedIndex doesn't work

Question

i have a from with many select tags , when the user submit the form i want to check if the user choose one option for all the select tags and this is my jquery code

Answer 1

var $this = $(this);
if($this.get(0).selectedIndex == 0) {

}

or just simple

this.selectedIndex; // not $this / $(this)

If no option it will return -1

here I showed all above cases