How to set value of one textbox to another on checkbox checked ?

Permanent address is same as Current address on checkbox click Javascript code.

Html Code:

<form method="post" >

    <input type="text" name="currentaddress" id="currentaddress" placeholder="Current Address" /><br>

    <input type="checkbox" onClick="return address()" name="accept" id="accept"><label for="accept">Same As Above<label><br>

    <input type="text" name="permanentaddress" id="permanentaddress"  placeholder="Permanent Address" />

</form>


Javascipt code:

(Copy-paste the following code in head section of your html page)

function address()
    {
        var chk=document.getElementById("accept").checked;
        if(chk)
        {
        var a1=document.getElementById("currentaddress").value;
        //alert(""+a1);
        document.getElementById("permanentaddress").value=a1;
        document.getElementById("permanentaddress").disabled=true;
        }
        else
        {
            document.getElementById("permanentaddress").disabled=false;
        }
    }

Live Demo