$( elem ).attr("checked") giving opposite results [duplicate]

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• .prop() vs .attr() 11 answers

Clicking checkbox should give alert checked if checked and give alert not checked if not. Here is the code:

<input type = "checkbox" id = "all" value="all" /> MyCheckbox

 <script src="jquery-2.1.4.js"></script>
<script type="text/javascript">
    $("input[type=checkbox]").click(function(){
    if ($(this).attr("checked")) {   //Hide everything
alert("checked");
}
else{
alert("not checked");
}
});
</script>

Initially checkbox is unchecked. As soon as I click it, debugger shows it checked value true. Now control should enter if{} block as its value is true but its entering in else{} block. (Am using breakpoints).

Why this is happening. Pls help am trying for hours.