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JavaScript：if else 语句多个条件

JavaScript

天涯尽头无女友 2021-08-20 18:15:38

JavaScript 新手，正在尝试创建学费计算器。我需要知道居住地，如果他们参加校园课程和学分，然后计算学费。我无法让 if else 语句起作用。该代码仅显示在校园课程中，但一旦成功，我将添加在线课程等。感谢您的帮助！如果我在每个课程类型之前询问居住问题，我会让这个计算器工作，但我只想问一次居住问题，然后将学费分配给 var onctut2。我还希望学生能够为 onchours1 输入小数，但我只能让整数起作用。我尝试了各种 if else 语句。<!doctype html> <html> <head> <meta charset="utf-8" /> <title>Tuition Calculator</title> <script type="text/javascript">// <![CDATA[ function formHandler(form) { var residency = eval(form.residency.value); var onctut1 = eval(form.onctut1.value); var onchours1 = eval(form.onchours1.value); var onctut2 = 0; var t1 = onctut2 * onchours1; var totalhours = onchours1; var oncfee1 = 0; var techfee1 = 0; var strecfee = 0; //Calculate on campus tut if (residency == "yes") && (onctut1 == "yes") { onctut2 = 252.00; } else if (residency == "no") && (onctut1 == "yes") { onctut2 = 554.00; } else { onctut2 = 0; } //Calculate on campus fees if (onchours1 == "1") { oncfee1 = 75.25; } else if (onchours1 == "2") { oncfee1 = 87.5; } else if (onchours1 == "3") { oncfee1 = 99.75; } else if (onchours1 == "4") { oncfee1 = 169.5; } else if (onchours1 == "5") { oncfee1 = 181.75; } else if (onchours1 == "6") { oncfee1 = 194.0; } else if (onchours1 == "7") { oncfee1 = 433.25; } else if (onchours1 == "8") { oncfee1 = 445.5; } else if (onchours1 == "9") 当我单击“计算成本”时，表单保持空白。

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3 回答

慕尼黑的夜晚无繁华

TA贡献1864条经验获得超6个赞

我想我已经解决了您的 T1 问题，我认为它正在按您的意愿工作！

<!doctype html>

<html>

<head>

<title>Tuition Calculator</title>

function formHandler(form) {

var residency = eval(form.residency.value);

var onctut1 = eval(form.onctut1.value);

var onchours1 = eval(form.onchours1.value);

var onctut2 = 0;

var totalhours = onchours1;

var oncfee1 = 0;

var techfee1 = 0;

var strecfee = 0;

//Calculate on campus tut

if (residency == 0 && onctut1 == 0) {

onctut2 = 252.00;

} else if (residency == 1 && onctut1 == 0) {

onctut2 = 554.00;

} else {

onctut2 = 0;

}

//Calculate on campus fees

if (onchours1 == "1") {

oncfee1 = 75.25;

} else if (onchours1 == "2") {

oncfee1 = 87.5;

} else if (onchours1 == "3") {

oncfee1 = 99.75;

} else if (onchours1 == "4") {

oncfee1 = 169.5;

} else if (onchours1 == "5") {

oncfee1 = 181.75;

} else if (onchours1 == "6") {

oncfee1 = 194.0;

} else if (onchours1 == "7") {

oncfee1 = 433.25;

} else if (onchours1 == "8") {

oncfee1 = 445.5;

} else if (onchours1 == "9") {

oncfee1 = 457.75;

} else if (onchours1 == "10") {

oncfee1 = 470.0;

} else if (onchours1 == "11") {

oncfee1 = 482.25;

} else if (onchours1 == "12") {

oncfee1 = 494.5;

} else if (onchours1 == "13") {

oncfee1 = 506.75;

} else if (onchours1 == "14") {

oncfee1 = 519.0;

} else if (onchours1 == "15") {

oncfee1 = 531.25;

} else if (onchours1 == "16") {

oncfee1 = 543.5;

} else {

oncfee1 = 0;

}

//Calculate on tech fee

if (totalhours == "1") {

techfee1 = 11.;

} else if (totalhours == "2") {

techfee1 = 22.;

} else if (totalhours == "3") {

techfee1 = 33.;

} else if (totalhours == "4") {

techfee1 = 44.;

} else if (totalhours == "5") {

techfee1 = 55.;

} else if (totalhours == "6") {

techfee1 = 66.;

} else if (totalhours == "7") {

techfee1 = 77.;

} else if (totalhours == "8") {

techfee1 = 88.;

} else if (totalhours == "9") {

techfee1 = 99.;

} else if (totalhours == "10") {

techfee1 = 110.;

} else if (totalhours == "11") {

techfee1 = 121.;

} else if (totalhours == "12") {

techfee1 = 132.;

} else if (totalhours == "13") {

techfee1 = 143.;

} else if (totalhours == "14") {

techfee1 = 154.;

} else if (totalhours == "15") {

techfee1 = 165.;

} else if (totalhours == "16") {

techfee1 = 165.;

} else {

techfee1 = 0;

}

//Calculate on student rec fee

if (totalhours > "0") {

strecfee = 4;

}

var fees1 = oncfee1;

var fees = fees1 + techfee1 + strecfee;

var t1 = onctut2 * onchours1;

var cost = t1 + fees;

form.t1.value = "$" + t1.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.fees.value = "$" + fees.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.costresult.value = "$" + cost.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.totalhours.value = "" + totalhours;

}

// ]]></script>

</head>

<body>

<div>

<table

id="AutoNumber1"

summary="calculate the cost per semester for

graduate students"

<tbody>

<tr>

<td colspan="2"><label for="residency">Are you a Resident? </label>

</select></td>

</tr>

<tr>

<td colspan="2"><label for="onctut1">Will you take an On campus class? </label>

</select></td>

</tr>

<tr>

<td colspan="2"><label for="onchours1">Select On campus class Credit Hours </label>

</select></td>

</tr>

<tr>

</tr>

<tr>

<td colspan="2"><button

name="CostResult"

onclick="javascript:formHandler(this.form)"

type="button"

> Calculate Cost </button></td>

</tr>

<tr>

</tr>

<tr>

<td><label for="t1">Tuition On Campus Class(es) </label></td>

</tr>

<tr>

</tr>

<tr>

<td><label for="costresult">Total Estimated Tuition/Fees Semester Cost </label></td>

<td><input

id="costresult"

name="costresult"

size="10"

type="text"

/></td>

</tr>

<tr>

<td><label for="totalhours">Total Credit Hours </label></td>

</tr>

</tbody>

</table>

</div>

</form>

</body>

</html>

反对回复 2021-08-20

海绵宝宝撒

TA贡献1809条经验获得超8个赞

三种类型的问题会在控制台中引发错误：

1)if语句指定的条件必须包含在括号中（整体），例如：

if (residency == "yes" && onctut1 == "yes")

或

if ( (residency == "yes") && (onctut1 == "yes") ).

2) 该eval函数（通常应尽可能避免）期望接收有效的 JavaScript 代码。删除eval呼叫可解决此问题。

3)>运算符需要数字，而不是字符串。在parseInt函数中包装比较可以解决这个问题。

这是实施了这些更改的工作版本：

*--已编辑--

我的原始答案仅进行了上述更改。

此修订版重新设计并简化了代码，并提供了更清晰的变量命名。

（我还没有完全测试过它，所以我不确定我的所有数学运算是否正确，但是更新它最应该做的是更改一些数字。）

*---

function formHandler(form) {

// Gets form inputs

var residencyInput = form.residency.value,

oncTutInput = form.onctut1.value,

oncHoursInput = form.onchours1.value;

// Converts each input (from String) to Boolean or Number (assumes valid input values)

var residencyBoolean = (residencyInput == "Yes"),

oncTutBoolean = (oncHoursInput == "Yes"),

oncHoursNumber = parseInt(oncHoursInput);

// Sets Hourly onc tut based on residency

if(residencyBoolean){ oncTutHourly = 252.00; }

else{ oncTutHourly = 554.00; }

// Calculates onc fees (defaults to zero, won't change unless onHoursNumber is positive)

let oncFee = 0;

if(oncHoursNumber > 0 && oncHoursNumber < 4){

oncFee = oncHoursNumber * 12.25 + 63;

}

else if(oncHoursNumber > 3 && oncHoursNumber < 7){

oncfee = oncHoursNumber * 12.25 + 120.5;

}

else if(oncHoursNumber > 6 && oncHoursNumber < 17){

oncfee = oncHoursNumber * 12.25 + 347.5;

}

// Calculates tech fee (defaults to zero, won't change unless onHoursNumber is positive)

let techFee = 0;

// If `oncHoursNumber` is above 15, techfee1 will be 165

if(oncHoursNumber > 0){

techfee = Math.min(oncHoursNumber * 11, 165);

}

//Calculates student rec fee

let strecFee = 0;

if(oncHoursNumber > "0"){ strecFee = 4; }

// Calculates final values

let oncTutTotal = oncHoursNumber * oncTutHourly;

let feesTotal = oncFee + techFee + strecFee;

let costTotal = oncTutTotal + feesTotal;

form.t1.value = "$" + oncTutTotal.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.fees.value = "$" + feesTotal.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.costresult.value = "$" + costTotal.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');

form.totalhours.value = "" + oncHoursNumber;

}

<div>

<table

id="AutoNumber1"

summary="calculate the cost per semester for

graduate students"

<tbody>

<tr>

<td colspan="2"><label for="residency">Are you a Resident? </label>

</select></td>

</tr>

<tr>

<td colspan="2"><label for="onctut1">Will you take an On campus class? </label>

</select></td>

</tr>

<tr>

<td colspan="2"><label for="onchours1">Select On campus class Credit Hours </label>

</select></td>

</tr>

<tr>

</tr>

<tr>

<td colspan="2"><button

name="CostResult"

onclick="javascript:formHandler(this.form)"

type="button"

> Calculate Cost </button></td>

</tr>

<tr>

</tr>

<tr>

<td><label for="t1">Tuition On Campus Class(es) </label></td>

</tr>

<tr>

</tr>

<tr>

<td><label for="costresult">Total Estimated Tuition/Fees Semester Cost </label></td>

<td><input

id="costresult"

name="costresult"

size="10"

type="text"

/></td>

</tr>

<tr>

<td><label for="totalhours">Total Credit Hours </label></td>

</tr>

</tbody>

</table>

</div>

</form>

反对回复 2021-08-20

LEATH

TA贡献1936条经验获得超6个赞

if (residency == "yes") && (onctut1 == "yes") {

onctut2 = 252.00;

} else if (residency == "no") && (onctut1 == "yes") {

onctut2 = 554.00;

} else {

onctut2 = 0;

}

我的猜测是，问题在于你需要在整个条件周围加上括号，而不是每个单独的条件。

if (residency == "yes" && onctut1 == "yes") {

onctut2 = 252.00;

} else if (residency == "no" && onctut1 == "yes") {

onctut2 = 554.00;

} else {

onctut2 = 0;

}

看起来您也可以简化代码，而不是为 techfee1 变量使用大量 if 语句，您可以执行以下操作：

totalhours = +totalhours; // convert it to a number

techfee1 = totalhours * 11;

if (totalhours === 16) {

techfee1 = 165;

}

if (totalhours > 16 || totalhours < 1) {

techfee1 = 0;

}

反对回复 2021-08-20

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JavaScript：if else 语句多个条件

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