Sort text in select

[Sophie Cameron]

We wrote code to sort select text but it is not efficient if there are more than 1,000 entries. Since select.options is read-only, we can't use Array.sort() to do it.

If you need to sort select entries, how would you do it?

Thanks,

[Eric Pascarello]

What are you trying to do with this, there might be a better way of doing it.

Where is the information coming from?

Eric

[Sophie Cameron]

Hi Eric,

What I want to do is when a new entry needs to be added to a select, I want it to be added alphabetically. The original select is already rendered alphabetically.

Here is my code to do it:

var newText = "new Text";
var newValue = "new Value"
 
for (var i = 0; i < mySelect.length; i++) {
  if (newText < mySelect.options[i].text) {
    // Reserve the entry at index of i for the new option
    for (var j = leftSelect.length; j > i; j--) {
      mySelect.options[j] = new Option(mySelect.options[j - 1].text, mySelect.options[j - 1].value);
    }
 
    mySelect.options[i] = new Option(newText, newValue);
    break;
  }
}

Many Option objects are created in the second loop, which is the bottleneck. The performance could be [bold]greatly[/bold] improved if the

mySelect.options[j] = new Option(mySelect.options[j - 1].text, mySelect.options[j - 1].value);

could be replaced with

mySelect.options[j] = mySelect.options[j - 1];

but actually not.

Thanks,

[Sophie Cameron]

The leftSelect in the second for loop should be mySelect.

Sorry about that.