How to optimize working with array in the following code in javascript?

Question

Is there a way to make the following code faster? It's becoming too slow, when length of array is more than 1000 records, especially in IE6.

  dbusers = data.split(";");
  $("#users").html("");
  for (i = 0; i < dbusers.length; i++) {
     if ($("#username").val() != "") {
        if (dbusers[i].indexOf($("#username").val()) != -1) {
           $("#users").append(dbusers[i] + "<br>");
        }
     } else {
        $("#users").append(dbusers[i] + "<br>");
     }
  }

Answer 1

Minimize the amount of work you do in the loop. Don't add stuff to the DOM in the loop, create a string.

var dbusers = data.split(";");
var username = $("#username").val();
var userlist = "";
if (username == "") {
    for (i = 0; i < dbusers.length; i++) {
        userlist += dbusers[i] + "<br>";
    }
} else {
    for (i = 0; i < dbusers.length; i++) {
        if (dbusers[i].indexOf(username) != -1) {
            userlist += dbusers[i] + "<br>";
        }
    }   
}   
$("#users").html(userlist);