datalist 如何判断输入是否是选项之一

Question

I was wondering why why I select 2 with a select tag it returns true in the console. But Whenever I select 2 in the datalist it returns false in the console.

In short I need the datalist to return tru. I need to it be true so that when the user enters in the input I can ensure that the user has enter in a option I wanted (one of the drop down menu options )

 function castvote() { var selected = document.getElementById('vote'); console.log("Chrome" in selected); }

 <input list="vote" onchange="castvote()" id="voteInput"> <datalist id="vote" > <option value="Chrome"> </datalist> <label>Choose a browser from this list: <input id = "a" list="browsers" name="myBrowser" style="width: 400px;" onclick="test()" /></label> <datalist id="browsers"> <option value="Chrome"> <option value="Firefox"> <option value="Internet Explorer"> <option value="Opera"> <option value="Safari"> <option value="Microsoft Edge"> </datalist>

Answer 1

You should try this. I just put ( .children ) at the getElementById() to get all children of datalist and the onChange() function put at the input tag.

       <input list="vote" onchange="castvote()" id="voteInput">
        <datalist id="vote" >
            <option value="2">
            <option value="3">
            <option value="4">
            <option value="5">
            <option value="6">
        </datalist>

        <script>
        function castvote() {
            var datalist = document.getElementById('vote').children;
            console.log("2" in datalist);
        }
        </script>