由於某種原因,當我輸入值時,所有的輸出是 undefined,NaN和我不知道爲什麼。我認爲 錯誤真的很簡單..所以我簡單的facepalm。對於我的代碼,對不起 ,我還是新來的JavaScript。另外,不要介意信用卡。爲什麼我的輸出Undefined或NaN?
function processAmount(){
var numOfLiters= parseInt(document.estore.noOfLiters.value);
var result;
var perLiterAmount;
var gasType;
switch(gasType){
case "Premium":
perLiterAmount= 50;
result= 50*numOfLiters;
break;
case "Diesel":
perLiterAmount= 38;
result= 38*numOfLiters;
break;
case "Unleaded":
perLiterAmount= 44;
result= 44*numOfLiters;
break;
}
var vat= result*0.12;
document.write("<p>Fuel Type: " + gasType + "</p>");
document.write("<p>Price per Liter amount: " + perLiterAmount + "</p>");
document.write("<p>Purchase Amount: " + result + "</p>");
document.write("<p>VAT: " + vat + "</p>");
document.write("<p>TOTAL AMOUNT: " + (result+vat) + "</p>");
document.write("<p>Credit Card : " + creditCard + "</p>");`
,這裏是形式:
<form name='estore' id='estore'>
<fieldset>
<legend>Gasoline eStore</legend>
<p>Enter gasoline type:
<select name='gastype' id='gastype'>
<option value="Premium"> Premium</option>
<option value="Unleaded"> Unleaded</option>
<option value="Diesel"> Diesel</option>
</select></p>
<p> Enter number of Liters:
<input type='number' name='noOfLiters' id='noOfLiters'/>
</p>
<p> Enter Credit Card Number:
<input type="number" name='creditCardNumber' id='creditCardNumber'/>
</p>
<p>
<input type='button' value='Submit'
onclick="processAmount()"/>
<input type='reset'/>
</p>
什麼是gasType? –
因爲'gasType'沒有被初始化。 –