HTML Checkbox onclick每次都发送相同的值

Question

I try to use two checkboxs with a value = "on". The other one is for rember after submit a form. Every time i click on this checkbox, they will always send "on".

What i do wrong ? Here is my code

var rdt = {
  updateScroll: function() {
    alert('klick scroll:' + gbi('scrollit').value);
    gbi('main').removeChild(gbi('icontent'));
    var ifr = document.createElement('iframe');
    ifr.id = 'icontent';
    ifr.src = gbi('urlinput').value;
    ifr.scrolling = (gbi('scrollit').value == 'on') ? 'yes' : 'no';
    gbi('scroll_hid').value = (gbi('scrollit').value == 'on') ? 'on' : 'off';
    gbi('main').appendChild(ifr);
    rdt.resizeView();
  }


}

function gbi(iD) {
  return document.getElementById(iD);
}

<input type="checkbox" id="scrollit" onclick="rdt.updateScroll()" checked>
<input type="hidden" name="scroll" id="scroll_hid" value="<?php echo $scroll ?>">

The parameter $scroll can predifine over URL, but the result was the same if i use it or if i dont use it.

</div>

Answer 1

This is because you are getting its value and its value is on. You have to get the value when it is checked like:

var value = null;
$('#scrollit').click(function(){
    if($(this).is('checked'))
    {
        value = $(this).val();
    }
});

In this case you will get its value when it is checked otherwise null