Dynamic Dropdown List Mixing Options

Question

Следующая функция javascript для создания динамического раскрывающегося списка, по-видимому, сохраняет параметры из предыдущего списка, когда выбран другой список, и не длиннее предыдущего.

function dynamicdropdown(listindex) 
{ 
    switch (listindex) 
    { 
    case "assaultrifle" : 
     document.getElementById("weaponbody").options[0]=new Option("Select Assault Rifle Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("ACR","acr"); 
     document.getElementById("weaponbody").options[2]=new Option("ACR-E","acre"); 
     document.getElementById("weaponbody").options[3]=new Option("AK-47","ak47"); 
     document.getElementById("weaponbody").options[4]=new Option("AK-74","ak74"); 
     document.getElementById("weaponbody").options[5]=new Option("Classic FAL","classicFal"); 
     document.getElementById("weaponbody").options[6]=new Option("LWRC M6","lwrcm6"); 
     document.getElementById("weaponbody").options[7]=new Option("Military M416","militaryM416"); 
     document.getElementById("weaponbody").options[8]=new Option("M4","m4"); 
     document.getElementById("weaponbody").options[9]=new Option("P416","p416"); 
     document.getElementById("weaponbody").options[10]=new Option("SCAR-L","scarl"); 
     document.getElementById("weaponbody").options[11]=new Option("Steyr Aug","steyrAug"); 
     document.getElementById("weaponbody").options[12]=new Option("LVOA-S","lvoas"); 
     document.getElementById("weaponbody").options[13]=new Option("SA-58","sa58"); 
     break; 
    case "lmg" : 
     document.getElementById("weaponbody").options[0]=new Option("Select LMG Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("L86 LSW","l86lsw"); 
     document.getElementById("weaponbody").options[2]=new Option("M249 B","m249b"); 
     document.getElementById("weaponbody").options[3]=new Option("M249 Tactical Para","m249TacticalPara"); 
     document.getElementById("weaponbody").options[4]=new Option("M60","m60"); 
     document.getElementById("weaponbody").options[5]=new Option("M60 E4","m60e4"); 
     document.getElementById("weaponbody").options[6]=new Option("M60 E6","m60e6"); 
     document.getElementById("weaponbody").options[7]=new Option("MK46","mk46"); 
     document.getElementById("weaponbody").options[8]=new Option("RPK-74","rpk74"); 
     break; 
    case "pistol" : 
     document.getElementById("weaponbody").options[0]=new Option("Select Pistol Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("M1911","m1911"); 
     document.getElementById("weaponbody").options[2]=new Option("M9","m9"); 
     document.getElementById("weaponbody").options[3]=new Option("PF45","pf45"); 
     document.getElementById("weaponbody").options[4]=new Option("586 Magnum","586Magnum"); 
     document.getElementById("weaponbody").options[5]=new Option("Px4 Storm","px4Storm"); 
     document.getElementById("weaponbody").options[6]=new Option("M9 A1","m9a1"); 
     document.getElementById("weaponbody").options[7]=new Option("Defiler","defiler"); 
     document.getElementById("weaponbody").options[8]=new Option("M45A1","m45a1"); 
     break; 
    case "shotgun" : 
     document.getElementById("weaponbody").options[0]=new Option("Select Shotgun Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("M1014","m1014"); 
     document.getElementById("weaponbody").options[2]=new Option("Super 90","super90"); 
     document.getElementById("weaponbody").options[3]=new Option("M870","shipped"); 
     document.getElementById("weaponbody").options[4]=new Option("SASG-12","sasg12"); 
     document.getElementById("weaponbody").options[5]=new Option("Double Barrel Shotgun","doubleBarrelShotgun"); 
     document.getElementById("weaponbody").options[6]=new Option("Saiga 12","saiga 12"); 
     break; 
    case "smg" : 
     document.getElementById("weaponbody").options[0]=new Option("Select SMG Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("MP5","mp5"); 
     document.getElementById("weaponbody").options[2]=new Option("MP5-A4 Burst Fire","mpa4BurstFire"); 
     document.getElementById("weaponbody").options[3]=new Option("T821","t821"); 
     document.getElementById("weaponbody").options[4]=new Option("SMG-9","smg9"); 
     document.getElementById("weaponbody").options[5]=new Option("Vector","vector"); 
     document.getElementById("weaponbody").options[6]=new Option("Black Market T821","blackMarkett821"); 
     document.getElementById("weaponbody").options[7]=new Option("AUG A3 Para XS","AUG A3 Para XS"); 
     break; 
    case "dmr" : 
     document.getElementById("weaponbody").options[0]=new Option("Select DMR Body",""); 
     document.getElementById("weaponbody").options[1]=new Option("M1A","m1a"); 
     document.getElementById("weaponbody").options[2]=new Option("SRS","srs"); 
     document.getElementById("weaponbody").options[3]=new Option("SOCOM 16","socom16"); 
     document.getElementById("weaponbody").options[4]=new Option("Mk17 SR","mk17sr"); 
     document.getElementById("weaponbody").options[5]=new Option("SCAR-H","scarh"); 
     document.getElementById("weaponbody").options[6]=new Option("M44","m44"); 
     break; 
    } 
    return true; 
} 

HTML, здесь:

<div class="sub_category_div" id="sub_category_div"> 
<label class="input-label">WEAPON BODY</label> 
    <script type="text/javascript" language="JavaScript"> 
    document.write('<select name="weaponbody" id="weaponbody"><option value="">Weapon Body</option></select>') 
    </script> 
</div> 

Пример список SMG смешивание со списком Штурмовой Винтовки показан на рисунке ниже:

Любых идей о почему это происходит, было бы полезно.

Answer 1

Я просто добавил:

document.getElementById('weaponbody').options.length = 0; 

к OnChange здесь:

<select id="weapontype" name="weapontype" onchange="javascript: dynamicdropdown(this.options[this.selectedIndex].value);"> 

Результат:

<select id="weapontype" name="weapontype" onchange="javascript: document.getElementById('weaponbody').options.length = 0; dynamicdropdown(this.options[this.selectedIndex].value);"> 

работает отлично.

Answer 2

Очистить варианты, прежде чем добавлять новые:

var select = document.getElementById("weaponbody"); 
while (select.firstChild) { 
    select.removeChild(select.firstChild); 
}