Enable And Disable Button using Javascript

HTML

<input type="button" value="Disable" onClick="disable()" id="disable">
<input type="button" value="Enable" onClick="enable()" id="enable" disabled="true">

JavaScript

function disable(){
            document.getElementById("disable").disabled = true;
            document.getElementById("enable").disabled = false;
        }
        function enable(){
            document.getElementById("disable").disabled = false;
            document.getElementById("enable").disabled = true;
        }

Example

Click Here to DEMO