ユーザーがプロンプトをキャンセルしたときにnull値にtextareaを設定しないようにするにはどうすればよいですか？

Question

これは、私がハイキャップデータ回路をテストする際に、統一された明確な注意を払うように設計しているツールの一部です。ユーザーがnull値にtextareaを入れるのを防ぐために、プロンプトをキャンセルしますか？私はこれを書いたときに雄牛の価値について完全に忘れました。私は！= "null"条件付きで試してみて、それは完全にテキストエリアを埋めるのを防ぎます。

<!-- Remarks Textarea Begin --><td><textarea 
id="REMARKSTEXTAREA" rows="10" cols="100">***CCSC*** 
     </textarea></td> 
<!-- Remarks Textarea End --> 

<!-- BEGIN ACCESS DROPDOWN MENU --> 
     <td style="text-align: center; width: 638px;"> 
     <select id="accessdropdownmenu"> 
     <option value="">MAKE A SELECTION</option> 
     <option value="1">ACCESSED CLLI @ XXX IN "A" 
DIRECTION…</option> 
     <option value="2">ACCESSEDCLLI @ XXX IN "Z" 
DIRECTION…</option> 
     <option value="3">ACCESSED CLLI @ XXX (FULLY 
IMBEDDED) IN "A" DIRECTION…</option> 
     <option value="4">ACCESSED CLLI @ XXX (FULLY 
IMBEDDED) IN "Z" DIRECTION…</option> 
     <option value=" GETTING IMMEDIATE AIS ALARM…">GETTING 
IMMEDIATE AIS ALARM…</option> 
     <option value=" GETTING IMMEDIATE RAI ALARM…">GETTING 
IMMEDIATE RAI ALARM…</option> 
     <option value="5">XXX MAPPED CORRECTLY TO XXX PER 
CLR/DLR…</option> 
     <option 
value=" CROSS CONNECTS DO NOT MATCH PER CLR/DLR INFO...">CROSS 
CONNECTS DO NOT MATCH PER CLR/DLR INFO...</option> 
     <option value=" NO DACS TEST POINTS PER CLR/DLR…">NO 
DACS TEST POINTS PER CLR/DLR…</option> 
     <option value=" NO REMOTE TEST ACCESS POINTS PER CLR/DLR…">NO 
REMOTE TEST ACCESS POINTS PER CLR/DLR…</option> 
     <option value="6">UNABLE TO ACCESS CLLI @ XXX...</option> 
     </select> 
     <script> 
var mytextboxaccess = document.getElementById('REMARKSTEXTAREA'); 
var mydropdownaccess = document.getElementById('accessdropdownmenu'); 
mydropdownaccess.onchange = function(){ 
if (mydropdownaccess.value == 1) { 
var CLLI = prompt("WHAT CLLI CODE ARE YOU ACCESSING?"); 
var ACCESSPOINT = prompt("WHAT ACCESS POINT ARE YOU USING?"); 
mytextboxaccess.value = mytextboxaccess.value + " ACCESSED " + CLLI + " @ " + ACCESSPOINT + " IN 'A' DIRECTION.."; this.value = "";} 
if (mydropdownaccess.value == 2) { 
var CLLI = prompt("WHAT CLLI CODE ARE YOU ACCESSING?"); var ACCESSPOINT = prompt("WHAT ACCESS POINT ARE YOU USING?"); 
mytextboxaccess.value = mytextboxaccess.value + " ACCESSED " + CLLI + " @ " + ACCESSPOINT + " IN 'Z' DIRECTION.."; this.value = "";} 
if (mydropdownaccess.value == 3) { 
var CLLI = prompt("WHAT CLLI CODE ARE YOU ACCESSING?"); 
var ACCESSPOINT = prompt("WHAT ACCESS POINT ARE YOU USING?"); 
mytextboxaccess.value = mytextboxaccess.value + " ACCESSED " + CLLI + " @ " + ACCESSPOINT + " (FULLY IMBEDDED) IN 'A' DIRECTION.."; this.value = "";} 
if (mydropdownaccess.value == 4) { 
var CLLI = prompt("WHAT CLLI CODE ARE YOU ACCESSING?"); 
var ACCESSPOINT = prompt("WHAT ACCESS POINT ARE YOU USING?"); 
mytextboxaccess.value = mytextboxaccess.value + " ACCESSED " + CLLI + " @ " + ACCESSPOINT + " (FULLY IMBEDDED) IN 'Z' DIRECTION.."; this.value = "";} 
if (mydropdownaccess.value == 5) { 
var ACCESSPOINT1 = prompt("WHAT ACCESS POINT DID YOU ACCESS?"); 
var ACCESSPOINT2 = prompt("WHAT ACCESS POINT IS IT MAPPED TO?"); mytextboxaccess.value = mytextboxaccess.value + " " + ACCESSPOINT1 + " MAPPED CORRECTLY TO " + ACCESSPOINT2 + " PER CLR/DLR.."; this.value = "";} 
if (mydropdownaccess.value == 6) { 
var CLLI = prompt("WHAT CLLI CODE WERE YOU ATTEMPTING TO ACCESS?"); 
var ACCESSPOINT = prompt("WHAT ACCESS POINT WERE YOU USING?"); 
mytextboxaccess.value = mytextboxaccess.value + " UNABLE TO ACCESS " + CLLI + " @ " + ACCESSPOINT + ".."; this.value = "";} 
else { 
mytextboxaccess.value = mytextboxaccess.value + mydropdownaccess.value + ".."; this.value = "";} 
} 
     </script> 
     </td> 
<!-- END ACCESS DROPDOWN MENU --> 

Answer 1

残念ながら、私はコメントすることはできませんが、あなたはそれがあるべき

if(CLLI != "null") { 
    // do stuff 
} 

を試してみました：

if (CLLI !== null) { 
    // do stuff 
} 

この問題にアプローチする別の方法はternary演算子を使用することです。

一つの例は、

if (mydropdownaccess.value == 1) { 
    var CLLI = prompt("WHAT CLLI CODE ARE YOU ACCESSING?"); 
    CLLI = (CLLI !== null) ? " ACCESSED " + CLLI : ''; 
    mytextboxaccess.value = mytextboxaccess.value + CLLI + " @ " + ACCESSPOINT + " (FULLY IMBEDDED) IN 'Z' DIRECTION.."; this.value = "";} 
} 

しかし、おそらくあなたのコードをリファクタリングするためにいくつかの時間を費やすことはあなたの利益になりますされる可能性があります。