有一些问题在做一个非常简单的包含JavaScript项目。
WeightedGPA附加了值，而不是在使用+ =
时添加它Caluclation我想做的是：加权平均GPA：尝试的小时数乘以每个课程的成绩点，然后除以总的尝试小时数
感谢任何帮助。已附上完整代码
<html>
<head>
</head>
<body>
<script type="text/javascript">
var courseValues = new Array();
var x = 0;
var debug = true;
function courseObjCreate()
{
var courseData = "";
courseData += document.getElementById("name").value;
courseData += ","
courseData += document.getElementById("number").value;
courseData += ","
courseData += document.getElementById("mark").value;
courseData += ","
courseData += document.getElementById("hours").value;
courseData += ","
courseData += document.getElementById("credits").value;
courseValues[x] = courseData;
alert("Course added!");
var elemName = document.getElementById("name");
elemName.value = "";
var elemNumber = document.getElementById("number");
elemNumber.value = "";
var elemMark = document.getElementById("mark");
elemMark.value = "";
var elemHours = document.getElementById("hours");
elemHours.value = "";
var elemCredits = document.getElementById("credits");
elemCredits.value = "";
x++;
}
</script>
<center>
<h1> Student transcript</h1>
<br>
<h2> Enter course details</h2>
<form>
Course name: <input id="name" type="text" /><br>
Course number: <input id="number" type="text" /><br>
Course mark: <input id="mark" type="text" /><br>
Course hours: <input id="hours" type="text" /><br>
Course credits: <input id="credits" type="text" /><br>
<input type="button" value="Submit" onClick ="courseObjCreate()"> Click me to add another course
<br>
<input type="button" value="Generate" onClick ="tblCall()"> Click me to generate the course table
<br>
</form>
<br>
<br>
<script type="text/javascript">
function createTable()
{
if(debug) console.log("Create Table Start");
var gpaSum = (0.0);
var hoursSum = 0;
var credits = 0;
var creditsSum = 0;
var gpaSum = (0.0)
var prnStrF = "";
var weightedGpa = (0.0)
if(debug) console.log("weightedGpa: " + weightedGpa);
prnStrF += '<table border="1" cellspacing="1" cellpadding="5">';
prnStrF += '<tr><td>Course name</td><td>Couse number</td><td>Course mark(percentage)</td><td>Course letter grade</td><td>Course Grade Point</td><td>Course hours</td><td>Course credits</td>';
for (var i = 0; i < courseValues.length; i++)
{
courseLetter ='';
courseGPA= (0.0).toFixed(2);
var coursePrintStr = courseValues[i].toString();
var prn = coursePrintStr.split(",")
if(debug) console.log("prn[2]: " + prn[2]);
var markNum = parseInt(prn[2]);
if(debug) console.log("MarkNum: " + markNum);
switch(true)
{
case (markNum < 50):
if(debug) console.log("less than 50");
courseLetter = 'F';
courseGPA = 0.0;
credits = 0;
weightedGpa += 0;
break;
case (markNum > 49 && markNum < 55):
if(debug) console.log("more than 49 less than 55");
courseLetter = 'D';
courseGPA = 1.0;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 54 && markNum < 60):
courseLetter = 'D+';
courseGPA = 1.3;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 59 && markNum < 63):
courseLetter = 'C-';
courseGPA = 1.7;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 62 && markNum < 67):
courseLetter = 'C';
courseGPA = 2.0;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 66 && markNum < 70):
courseLetter = 'C+';
courseGPA = 2.3;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 69 && markNum < 73):
courseLetter = 'B-';
courseGPA = 2.7;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 72 && markNum < 77):
courseLetter = 'B';
courseGPA = 3.0;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 76 && markNum < 80):
courseLetter = 'B+';
courseGPA = 3.3;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 79 && markNum < 85):
if(debug) console.log("MarkNumInCase: " + markNum);
courseLetter = 'A-';
courseGPA = 3.7;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
case (markNum > 84):
courseLetter = 'A';
courseGPA = 4.0;
credits = parseInt(prn[4]);
weightedGpa += parseInt(courseGPA * parseInt(prn[3]));
break;
default:
alert("Something broke in the switch case. Probably a String input instead of an int");
}
courseGPA = courseGPA.toFixed(2);
if(debug) console.log("gpaSum: " + gpaSum);
creditsSum += credits;
if(debug) console.log("creditsSum: " + creditsSum);
hoursSum += parseInt(prn[3]);
if(debug) console.log("hoursSum: " + hoursSum);
if(debug) console.log("weightedGpa: " + weightedGpa);
weightedGpa = (weightedGpa/hoursSum).toFixed(2);
if(debug) console.log(prnStrF);
prnStrF +='<tr>';
prnStrF += '<td>' + String(prn[0]) + '</td>' + '<td>' + String(prn[1]) + '</td>' + '<td>' + String(prn[2]) + "%" + '</td>'+ '<td>'+ String(courseLetter) + '</td>' + '<td>' + String(courseGPA) +'</td>' +'<td>' + String(prn[3]) + '</td>' +'<td>' + String(prn[4]) + '</td>';
prnStrF += '</tr>';
}
prnStrF += '</table>';
if(debug) console.log("hoursSum: " + hoursSum);
if(debug) console.log("creditsSum: " + creditsSum);
if(debug) console.log("weightedGpa: " + weightedGpa);
prnStrF += '<br><br>';
prnStrF +='<table border="1" cellspacing="1" cellpadding="5">';
prnStrF += '<tr><td><b>Report</td><td></td><td>Attemped hours</td><td>Earned credits </td><td>Weighted Average GPA</td></b></tr>';
prnStrF += '<tr><td><b>Report</td><td></td><td>'+ String(hoursSum) + '</td><td>' + String(creditsSum) +' </td><td>'+ String(weightedGpa)+'</b></td></tr>';
prnStrF += '</table>';
if(debug) console.log(prnStrF);
return prnStrF;
}
</script>
<script type="text/javascript">
function tblCall()
{
document.getElementById('generateHere').innerHTML = createTable();
}
</script>
<br>
<br>
<div id='generateHere'></div>
</center>
</body>
</html>
答案 0 :(得分：1)
你想通过使用parseint或parsefloat函数强制将所有内容视为一个数字 - 因为它是，当JS怀疑某个字符串是一个字符串时，+将意味着串联。
在我看来，你正在做一个奇怪的总和 - 你“添加”的第一件事是名字，这可能是一个字符串。为什么要形成这个总和（而不是两个单独变量中的等级和信用小时总和，所以你可以计算你声称要做的加权平均值。）
也许您应该考虑将不同的字段累积到一个数组集合中 - 当您汇总了所有数据时，您可以计算小时数组的总和以及（小时*等级）的总和，这样您就可以得到加权平均值。
你还需要更多的东西来重新开始吗？
答案 1 :(得分：0)
在宣布加权的Gpa之后你错过了一个分号，这只是一个错字吗？它可能搞砸了宣言。
答案 2 :(得分：0)
更改你的行'var courseData =“”;'到'var courseData = 0;'这应该可以解决问题。
声明使用“”告诉javascript courseData是一个字符串，所以你的+ =操作将被视为连接而不是数学函数。