$( elem ).attr("checked") giving opposite results
This question already has an answer here:
The problem is that you are checking checked attribute which is not going to be removed or added when checked status changes. This is a nuance you should be aware about properties and attributes. You need to compare checked property of the checkbox element, not attribute.
Also it's better to use change event handler (because you can check checkbox not only with mouse click but with keyboard too).
$("input[type=checkbox]").change(function() {
if (this.checked) {
alert("checked");
}
else {
alert("not checked");
}
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type = "checkbox" id = "all" value="all" /> MyCheckboxThis :
$(this).attr("checked") //in old versions of jquery this yield "checked" ,
Yields undefined which is a Falsy statement.
As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set
You can either use :
if ($(this).is(":checked"))
or
$(this).prop("checked")
As of jQuery 1.6 , the .attr() method returns undefined for attributes that have not been set. To retrieve and change DOM properties such as the checked, selected, or disabled state of form elements, use the .prop() method.
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