I have a lookup field in the list and it is has duplicate values.

I found the below code and tried to use it.

<script type="text/javascript" src="//code.jquery.com/jquery-1.11.0.min.js"></script>
$( document ).ready(function() {
var usedNames = {};
$("select[name='Team'] > option").each(function () {
    if(usedNames[this.text]) {
    } else {
        usedNames[this.text] = this.value;


But this doesn't work, what extra things do I need to do?

  • Show some sample input/output. or screen shots Commented Nov 19, 2015 at 12:46
  • 2
    It would be best to use the enforce unique values setting on your lookup column in your list so you don't get duplicates. This code is only going to "fix" it on the display, not resolve your actual problems. Commented Nov 19, 2015 at 12:49
  • I want to do it for EditForm.aspx page...and also applying enforce unique values doesnt work
    – KumarV
    Commented Nov 19, 2015 at 12:52
  • select[name='Team'] is that correct? check it inspecting DOM from browser Commented Nov 19, 2015 at 12:57
  • If you enable force unique values, you then have to go back and clean up the duplicate items. You will have a clean list, no duplicates, and no more future duplicates. Commented Nov 19, 2015 at 13:08

3 Answers 3


Your code worked for me I have just changed the selector.

$("select[name='Team'] > option")

Instead of above

$("select[title='Name of your column'] > option")

I have replaced name with title as I did not find it in the DOM

enter image description here

  • 2
    While it works, it doesn't fix your underlying problem though Commented Nov 19, 2015 at 13:27
  • I agree. I have just tried to solve his js problem. OP should follow your suggestion for best practice @EricAlexander Commented Nov 19, 2015 at 13:30
  • Has anyone asked OP if the underlying List can be set to No Duplicates? I have come accross multiple Master-Detail use cases where we could not and needed the same remove-duplicates functionality. Commented Nov 20, 2015 at 8:23
  • It can be I guess as OP has said applying enforce unique values doesnt work in one of his comment. @DannyEngelman Commented Nov 20, 2015 at 8:28
  • My assumption by "it doesn't work" was that he didn't clean up the list data thinking that would solve the problem, when it wouldn't. Commented Nov 20, 2015 at 12:54

Your underlying problem is your relational list allows duplicate values to be inserted and gives you duplicate values when used in your forms. The fix, and not the bandaid solution, is to enable the enforce unique values on the lookup field in the lookup list and delete the duplicate entries.


You do not want to remove the Selected value from your dropdown

and do not need jQuery

var doubles=[];
var select=document.querySelectorAll("select[id^=Name]")[0];
console.log(select.childNodes);//must return a nodeList
[].slice.call(select.childNodes).forEach(function(el,n){//convert nodeList to array
    var v=el.innerHTML;
    if(el.selected) {
    } else {

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