onClick function returns undefined

Question

For some reason, the following code does not work properly:

<input onclick="$(function(){ alert($(this).attr('checked')); })" name="step1[agree]" id="step1_agree" value="1" type="checkbox">

It alerts with undefined. I have also tried doing something like this:

onclick="$(function(){ var chk=$(this); alert(chk.attr('id')); })"

... but ends up with the same result. What am I doing wrong and how can I fix this?

Answer 1

<input onclick="alert($(this).attr('checked'));" name="step1[agree]" id="step1_agree" value="1" type="checkbox">

But a better option would be

<input name="step1[agree]" id="step1_agree" value="1" type="checkbox">

$('#step1_agree').click(function() {
  alert($(this).attr('checked));
});