How to disable textbox depending on checkbox checked

Question

Can anyone please tell me how to disable a textbox, if a checkbox is checked, and enable textbox if the checkbox is not checked?

Answer 1

Put this in the checkbox:

onclick="document.getElementById('IdOfTheTextbox').disabled=this.checked;"

Answer 2

    <input type="text" id="textBox">
    <input type="checkbox" id="checkBox" onclick="enableDisable(this.checked, 'textBox')">
    <script language="javascript">
    function enableDisable(bEnable, textBoxID)
    {
         document.getElementById(textBoxID).disabled = !bEnable
    }
</script>