如何添加「選擇」使用javascript選擇選項

Question

我有以下代碼，我試圖添加「選擇」動態選項，當用戶選擇一個選項。我怎樣才能使用Javascript？ 例如當用戶選擇 「糖果」 我想補充<option value="candy" selected>Candy</option>

function urlDirect() { 
 
    var businessTypeSelected = document.getElementById("BusinessType").value; 
 
    //alert("x " +x); 
 
    if (businessTypeSelected != "") { 
 
    window.location.href = location.host + businessTypeSelected; 
 
    document.getElementById("BusinessType").selectedIndex = document.getElementById("BusinessType").selectedIndex; 
 
    } else { 
 

 
    } 
 
}

<span class="custom-dropdown custom-dropdown--blue custom-dropdown--large"> 
 
    <select id="BusinessType" class="custom-dropdown__select custom-dropdown__select--blue" onChange="urlDirect()"> 
 
    <option value="default">Select your business type</option> 
 
    <option value="auto">Auto </option> 
 
    <option value="aero">Aeroplane</option> 
 
    <option value="film">Film</option> 
 
    <option value="candy">Candy</option> 
 
    </select> 
 
</span>

Answer 1

這應該這樣做：

var select = document.getElementById('BusinessType'); 
select.addEventListener('change', function() { 

    select.options[select.selectedIndex].setAttribute('selected'); 
}); 

而且我建議你改變id的名字至business-type，因爲CSS沒有寫在camelCase中。