Perform action when clicking HTML5 datalist option

问题:

I'm using a <datalist>

<datalist id="items"></datalist>

And using AJAX to populate the list

 function callServer (input) {
    xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function(){
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200){
            //return the JSON object
            console.log(xmlhttp.responseText);
            var arr = JSON.parse(xmlhttp.responseText);
            var parentDiv = document.getElementById('items');
            parentDiv.innerHTML = "";
            //fill the options in the document
            for(var x = 0; x < arr.length; x++) {
                var option = document.createElement('option');
                option.value = arr[x][0];
                option.innerHTML = arr[x][1];
                //add each autocomplete option to the 'list'
                option.addEventListener("click", function() {
                  console.log("Test");
                });
                parentDiv.appendChild(option);
            };

        }
    }
    xmlhttp.open("GET", "incl/search.php?value="+input.value, true);
    xmlhttp.send();
}

However I can't get it to perform an action when I click on a selection in the datalist, for example if I type in "Ref F" and the item "Ref flowers" comes up, if I click on it I need to execute an event.

How can I do this?

option.addEventListener("click", function() {
option.addEventListener("onclick", function() {
option.addEventListener("change", function() {

回答1:

Sorry for digging up this question, but I've had a similar problem and have a solution, that should work for you, too.

function onInput() {
    var val = document.getElementById("input").value;
    var opts = document.getElementById('dlist').childNodes;
    for (var i = 0; i < opts.length; i++) {
      if (opts[i].value === val) {
        // An item was selected from the list!
        // yourCallbackHere()
        alert(opts[i].value);
        break;
      }
    }
  }

<input type='text' oninput='onInput()' id='input' list='dlist' />

<datalist id='dlist'>
  <option value='Value1'>Text1</option>
  <option value='Value2'>Text2</option>
</datalist>

This solution is derived from Stephan Mullers solution. It should work with a dynamically populated datalist as well.

Unfortunaltely there is no way to tell whether the user clicked on an item from the datalist or selected it by pressing the tab-key or typed the whole string by hand.

回答2:

Due to the lack of events available for <datalist> elements, there is no way to a selection from the suggestions other than watching the input's events (change, input, etc). Also see my answer here: Determine if an element was selected from HTML 5 datalist by pressing enter key

To check if a selection was picked from the list, you should compare each change to the available options. This means the event will also fire when a user enters an exact value manually, there is no way to stop this.

document.querySelector('input[list="items"]').addEventListener('input', onInput);

function onInput(e) {
   var input = e.target,
       val = input.value;
       list = input.getAttribute('list'),
       options = document.getElementById(list).childNodes;

  for(var i = 0; i < options.length; i++) {
    if(options[i].innerText === val) {
      // An item was selected from the list!
      // yourCallbackHere()
      alert('item selected: ' + val);
      break;
    }
  }
}

<input list="items" type="text" />
<datalist id="items">
  <option>item 1</option>
  <option>item 2</option>
</datalist>

回答3:

Datalist don't support click listener and OnInput is very costly, checking everytime all the list if anything change.

What I did was using:

document.querySelector('#inputName').addEventListener("focusout", onInput);

FocusOut will be triggered everytime a client click the input text and than click anywhere else. If they clicked the text, than clicked somewhere else I assume they put the value they wanted.

To check if the value is valid you do the same as the input:

   function onInput(e) {
        var val = document.querySelector('#inputName').value;
        options = document.getElementById('datalist').childNodes;
        for(var i = 0; i < options.length; i++) {
             if(options[i].innerText === val) {
                  console.log(val);
                  break;
             }
        }
    }