Question

1.我在代码的第一个注释中包含了我想要组合的两行。如果你能指出我需要做的事情，那真的会有所帮助。我刚刚开始使用javascript。如果你能推荐任何书籍，请告诉我。我正在阅读murach系列书籍，它真的很有帮助。

    /*The two statements i want to combine are 
    entry = parseInt(entry);
    var score1 = entry; */

    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">  
        <title>Average Test Scores</title>
        <script>
            var entry;
            var average;
            var total = 0;

            //get 3 scores from user and add them together
            entry = prompt("Enter test score");
            entry = parseInt(entry);
            var score1 = entry;
            total = total + score1;

            entry = prompt("Enter test score");
            entry = parseInt(entry);
            var score2;
            total = total + score2;

            entry = prompt("Enter test score");
            entry = parseInt(entry);
            var score3 = entry;
            total = total + score3;

            //calculate the average
            average = parseInt(total/3);
        </script>
    </head>
    <body>
        <script>
            document.write("<h1>The Test Scores App</h1>");
            document.write("Score 1 = " + score1 + "<br>" +
                "Score 2 = " + score2 + "<br>" +
                "Score 3 = " + score3 + "<br><br>" +
                "Average score = " + average + "<br><br>");
        </script>
        Thanks for using the Test Scores application!
    </body>
    </html>

Answer 1

Addition assignment， addition assignment运算符将right operand的值添加到变量中，并将结果赋给变量。

Unary plus (+)， unary plus operator位于其操作数之前，并计算其操作数，但尝试将其转换为number，如果尚未的话。

简化版：

var total = 0;
var score1 = +prompt("Enter test score"); //Cast it to Number
total += score1; //Add it to total
var score2 = +prompt("Enter test score");
total += score2;
var score3 = +prompt("Enter test score");
total += score3;
var average = parseInt(total / 3);
document.write("<h1>The Test Scores App</h1>");
document.write("Score 1 = " + score1 + "<br>" +
  "Score 2 = " + score2 + "<br>" +
  "Score 3 = " + score3 + "<br><br>" +
  "Average score = " + average + "<br><br>");

如何组合这些特定的Javascript语句？

1 个答案: