Remove duplicate elements from a drop down list using javascript

Answer 1

This is @DanDavis answer for reference, I'm adding it as, you know, public service. Plus a bit of formatting and a couple of alternatives to cover similar use cases.

var fruits = document.getElementById("Fruits");

[].slice.call(fruits.options)
  .map(function(a){
    if(this[a.value]){ 
      fruits.removeChild(a); 
    } else { 
      this[a.value]=1; 
    } 
  },{});

If you are working with a select populated by a database (a pretty obvious use case) and the values are ids and the innerText is the duplicates you want to remove. Then instead you'd want:

[].slice.call(fruits.options)
  .map(function(a){
    if(this[a.innerText]){ 
      fruits.removeChild(a); 
    } else { 
      this[a.innerText]=1; 
    } 
  },{}); 

Furthermore, if you want to retain the selected option (it might not be the first occurrence matched.) Try this:

[].slice.call(fruits.options)
  .map(function(a){
    if(this[a.innerText]){ 
      if(!a.selected) fruits.removeChild(a); 
    } else { 
      this[a.innerText]=1; 
    } 
  },{});