I wanna create select drop down list where selected value will be depends on input value. Example:
If i write 0 in `<input type='text' name='answer' id="ans" oninput="myFunction();">` than will be selected dynamically value NO.

```
<select id="abcd">
<option value="1">OK</option>
<option value="0">NO</option>    
</select> 

```

My attempts

```
 function myFunction() {      
var x = document.getElementById('ocena7');      
if (x == 0)
{
 document.getElementById("abcd").selectedIndex = 2;
}}

```

Greetings