keypress random from array in to form

Hello I'm trying to make my form so when you try to input your name it will randomly pick one from the array and insert that but i cant seem to get it to work.

 <script type="text/javascript">
    var val=""
    var counter="0"
    Name=new array()
    DOB=new array()
    POB=new array()
    Name[0]="Donald Trump";
    Name[1]="Tony Abbott";
    Name[2]="Malcolm Turnbull";
    Name[3]="Kevin Rudd";
    Name[4]="Bill Shorten";
    DOB[0]="14/06/1964";
    DOB[1]="4/11/1957";
    DOB[2]="24/10/1954";
    DOB[3]="21/11/1957";
    DOB[4]="12/05/1967
    POB[0]="New York";
    POB[1]="London UK";
    POB[2]="Sydney";
    POB[3]="Nambour";
    POB[4]="Melbourne";

    x=[Math.floor(Math.random() * Name.length)

    function changer(){
    if (counter>=Name[x].lenght){
    return false}
    else{
    val+=Name[x].charAt(counter)
    document.myform.mytext.value=val
    counter++
    return false
    }
    }
    function resetit(){
    alert("Thanks for feed back. Have a nice day.")
    document.myform.mytext.value=""
    counter="0"
    val=""
    x=[Math.floor(Math.random() * Name.length)
    }

    </script>