你可以在单行代码中使用jQuery的$（this）来修改元素吗？

Question

I'm working on a placeholder function in jquery. Right now, I just want the form element to change its value to whatever its placeholder is. I tried the following code:

$('input:text').val($(this).attr('placeholder'));

But it doesn't work. After testing it a little, I realized the problem is with using $(this) in that context. How can I change this so that it will loop through all form elements and change their value to their placeholder attribute?

Answer 1

$('input:text').val(function() {
    return $(this).attr('placeholder');
});

or:

$('input:text').attr('value', function() {
    return $(this).attr('placeholder');
});

And here's a live demo .

Answer 2

Most of these setter jQuery functions provide a way to specify a function whose return value will be used. This is a way to make use of $(this) .

$('input:text').val(function () {
  return $(this).attr('placeholder');
});

jQuery val() Reference