.prop('checked',false) or .removeAttr('checked')?

jQuery 3

As of jQuery 3, removeAttr does not set the corresponding property to false anymore:

Prior to jQuery 3.0, using .removeAttr() on a boolean attribute such as checked, selected, or readonly would also set the corresponding named property to false. This behavior was required for ancient versions of Internet Explorer but is not correct for modern browsers because the attribute represents the initial value and the property represents the current (dynamic) value.

It is almost always a mistake to use .removeAttr( "checked" ) on a DOM element. The only time it might be useful is if the DOM is later going to be serialized back to an HTML string. In all other cases, .prop( "checked", false ) should be used instead.

Changelog

Hence only .prop('checked',false) is correct way when using this version.

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Original answer (from 2011):

For attributes which have underlying boolean properties (of which checked is one), removeAttr automatically sets the underlying property to false. (Note that this is among the backwards-compatibility "fixes" added in jQuery 1.6.1).

So, either will work... but the second example you gave (using prop) is the more correct of the two. If your goal is to uncheck the checkbox, you really do want to affect the property, not the attribute, and there's no need to go through removeAttr to do that.

use checked : true, false property of the checkbox.

jQuery:

if($('input[type=checkbox]').is(':checked')) {
    $(this).prop('checked',true);
} else {
    $(this).prop('checked',false);
}

I recommend to use both, prop and attr because I had problems with Chrome and I solved it using both functions.

if ($(':checkbox').is(':checked')){
    $(':checkbox').prop('checked', true).attr('checked', 'checked');
}
else {
    $(':checkbox').prop('checked', false).removeAttr('checked');
}