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Posted 21 Aug 2003

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Autocomplete edit control for Javascript

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3.25/5 (22 votes)
21 Aug 2003
Shows how to implement a Javascript based autocomplete edit control


This is a HTML control which integrates autocomplete into the standard textbox. By adding a few lines of code, you can turn any standard textboxes into a user friendly and a rather powerful control.

How it works

Whenever the user types anything in the textbox, the onkeyup event is fired, and the script calls a function. The current text in the textbox is then compared lexically with an array of strings.

Javascript code

fruits = new Array('apple','pear','orange',
names = new Array('tom','dick','harry','john','petter','foo','bar');
function autocomplete(n,ac_array){
    if (n.value == "") return 0;
    if (event.keyCode == 8 && n.backspace){
        n.value = n.value.substr(0,n.value.length-1);
        n.backspace = false;

    var r = n.createTextRange();    
    tmp= n.value;
    if (tmp == "")return 0;
    for (z=0;z<ac_array.length;z++){
        tmp2 = ac_array[z];
        count = 0;
        for (i = 0;i<tmp.length;i++){
            if (tmp2.charAt(i) == tmp.charAt(i)){
        if (count == tmp.length){
            diff = tmp2.length - tmp.length;
            if (diff <= 0) break;
            kap = "";
            for (i=0;i<tmp2.length;i++){
                if (i >= tmp.length) kap += tmp2.charAt(i);
            n.backspace = true;
            r.text += kap;
            return 0;
    n.backspace = false;
    return 0;

<input name='fruit' type='text' class='textbox' title="Opening" 
    onkeyup="autocomplete(this,fruits)" size="20">
<input name='Name' type='text' class='textbox' title="Opening" 
    backspace='false' onkeyup="autocomplete(this,names)" size="20">

How to use the code

  1. You must define the array of strings which you want to have autocompleted.
    fruits = new Array('apple','pear','orange','mango','durain',
  2. Copy the entire autocomplete function and put it somewhere in your code.
  3. Add the event onkeyup='autocomplete(this,fruits)' in the textbox. Note that the 2nd argument should tally with the array name you defined at 1.
  4. Add the property backspace='false' in the textbox. The backspace property is applicable when a user press backspace in the textbox. It gets very irritating without the boolean; i.e. when the user press backspace, the highlighted characters get deleted, but it will automatically be replaced by the same characters due to the autocomplete.


  1. I've tested the autocomplete control with an array of size 150. The speed was pretty reasonable on my computer (P3 700Mhz). However, I'm sure the autocomplete function's string-matching algorithm can be further improved upon.
  2. Allow for case insensitive string-matching


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Comments and Discussions

GeneralMy vote of 1 Pin
hsnfrz3-Dec-12 2:59
Memberhsnfrz3-Dec-12 2:59 
GeneralMy vote of 1 Pin
Risvile28-Sep-11 6:00
MemberRisvile28-Sep-11 6:00 
GeneralAutoComplete text box using PHP PEAR Class Pin
elizas8-Mar-10 2:27
Memberelizas8-Mar-10 2:27 
GeneralMy vote of 2 Pin
gopimayiru22-May-09 3:06
Membergopimayiru22-May-09 3:06 
GeneralNot working Pin
Member 246109727-May-08 23:42
MemberMember 246109727-May-08 23:42 
QuestionAutocompletion Pin
Pratheesh Rajan4-Oct-07 3:17
MemberPratheesh Rajan4-Oct-07 3:17 
GeneralIs it possible to view all elements' list on particular character press Pin
anil22kar9-Sep-07 22:33
Memberanil22kar9-Sep-07 22:33 
GeneralProblem with 2 Edit Control !!! Pin
Steeve_globetrotter4-May-06 4:18
MemberSteeve_globetrotter4-May-06 4:18 
GeneralRe: Problem with 2 Edit Control !!! Pin
tah siah rek ngaran naon deui18-Dec-12 8:44
Membertah siah rek ngaran naon deui18-Dec-12 8:44 
Generalnew version Pin
davidlars9921-Feb-06 10:32
Memberdavidlars9921-Feb-06 10:32 
Generalmozilla Pin
vadd__26-Feb-05 5:35
sussvadd__26-Feb-05 5:35 
GeneralMuch better... Pin
packard7526-Oct-04 20:38
Memberpackard7526-Oct-04 20:38 
GeneralRe: Much better... Pin
zichun27-Feb-05 22:35
Memberzichun27-Feb-05 22:35 
GeneralNot working with mozilla Pin
Anonymous24-Jun-04 7:41
MemberAnonymous24-Jun-04 7:41 
GeneralTo complete in the hole textrange.. Pin
Anonymous25-Feb-04 3:02
MemberAnonymous25-Feb-04 3:02 
GeneralError Pin
Peter, The Pumpkin Eater17-Jan-04 18:34
MemberPeter, The Pumpkin Eater17-Jan-04 18:34 
GeneralRe: Error Pin
zichun17-Jan-04 18:55
Memberzichun17-Jan-04 18:55 
GeneralRe: Error Pin
Peter, The Pumpkin Eater17-Jan-04 19:35
MemberPeter, The Pumpkin Eater17-Jan-04 19:35 
GeneralRe: Error Pin
zichun17-Jan-04 20:22
Memberzichun17-Jan-04 20:22 
GeneralMake Case Insensitive Pin
The Silverlord5-Sep-03 0:16
sussThe Silverlord5-Sep-03 0:16 
GeneralRe: Make Case Insensitive Pin
zichun5-Sep-03 6:35
Memberzichun5-Sep-03 6:35 
QuestionHow about a sever control? Pin
Paul Haley29-Aug-03 13:07
MemberPaul Haley29-Aug-03 13:07 
AnswerRe: How about a sever control? Pin
chenggn8-Apr-06 6:22
Memberchenggn8-Apr-06 6:22 
GeneralAll OK, but ... Pin
Mandalay23-Aug-03 21:45
MemberMandalay23-Aug-03 21:45 
GeneralRe: All OK, but ... Pin
zichun24-Aug-03 4:35
Memberzichun24-Aug-03 4:35 

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