Auto-populating user info from database
given that you duplicate nearly the whole $.ajax() call you can extract it into a function and add a parameter where it differs::

function doAjax(dataType, myval){
    $.ajax({
        contentType: "application/json; charset=utf-8",
        url: 'http://myserver.com/helpdesk/check_json.php',
        dataType: 'json',
        data: {type: dataType, term: myval},
        success: function (data) {
            if(typeof data == "undefined" | data == null | data.length == 0){
            alert("No Result");
            document.getElementById("form1").reset();
            return};
            //console.log(data);
            $("#empnum").val(data[0].empnum);
            $("#ext").val(data[0].extension);
            $("#omobile").val(data[0].omobile);
            $("#pmobile").val(data[0].pmobile);
            $("#ename").val(data[0].ename);
            $("#name").val(data[0].empnum);
            $("#email").val(data[0].email);
        },
        error: function (result) {
            alert("Error");
        }
    });
}