組合框驗證

Question

內容這是Java腳本code.for驗證組合框..驗證不正常工作..我需要你的幫助..plz幫助我..如果用戶不選擇它必須顯示警報箱體爲所有的樹

<script type="text/javascript"> 
function checkseats() { 
    if (!document.getElementsByName("seats")[0].selectedIndex == 1) { 
     alert("Select No of Seats"); 
     return false; 
    } 
    return true; 
} 

function checkmovie() { 
    if (document.getElementsByName("movie")[0].selectedIndex == 2) { 
     alert("Please select Movie from the list"); 
     return false; 
    } 
    return true; 
} 

function checkdate() { 
    if (document.getElementsByName("date")[0].selectedIndex == 3) { 
     alert("Please select Date from the list"); 
     return false; 
    } 
    return true; 
} 

function validate() { 
    checkdate(); 
    checkseats(); 
    checkmovie(); 
} 
</script> 

Answer 1

我想你想這個代替，

if (document.forms["yourFormName"].seats.value == "0"){ 
    alert("Select No of Seats"); 
    return false; 
    } 
    return true; 
}