如何添加“选择”使用javascript选择选项

Question

我有以下代码，我试图添加“选择”动态选项，当用户选择一个选项。我怎样才能使用Javascript？ 例如当用户选择 “糖果” 我想补充<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

这应该这样做：

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

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

而且我建议你改变id的名字至business-type，因为CSS没有写在camelCase中。