选中复选框时如何启用按钮

Question

I have codes like this

<div class="checkbox">

            <input type="checkbox" id="checkme" value ="accept"/>
                        <label>I have read and agree to the terms and conditions</label>
                                    <p><input type="submit" name="submit" value="Order now!" id="sub1" disabled="disabled"/></p>

I was trying to put this Jscript below of codes:

<script>
$(document).ready(function() {
    var the_terms = $("#checkme");

    the_terms.click(function() {
        if ($(this).is(":checked")) {
            $("#sub1").removeAttr("disabled");
        } else {
            $("#sub1").attr("disabled", "disabled");
        }
    });
}); 
                        </script>

However it does not work at all. I already follow all guides on internet. Anyone can help what part i did wrong? Is there any additional codes beside these?'

Oh and this on php format

EDIT: Done this too

                                                    <script>
var checker = document.getElementById('checkme');
var sendbtn = document.getElementById('sub1');
checker.onchange = function() {
  sendbtn.disabled = !!this.checked;
};
                        </script>

But how do i change to disable when unchecked?

Answer 1

Simply use jquery change event like this :

$(document).ready(function() {

    $('#checkme').change(function() {
        if ($(this).is(":checked")) {
            $("#sub1").removeAttr("disabled");
        } else {
            $("#sub1").attr("disabled", "disabled");
        }
    });
});