20、JavaScript 控制语句全解析

JavaScript 控制语句全解析

1. JavaScript 控制语句基础

1.1 控制语句堆叠

控制语句可以按顺序堆叠。例如，在某些代码中， while 语句之后紧接着是 if...else 语句。以下是一个示例：

<!-- 代码示例 -->
<script type = "text/javascript">
    // 初始化变量
    var gradeCounter = 0;
    var total = 0;
    var gradeValue;
    var grade;

    // while 语句
    while ( gradeValue != -1 ) {
        // add gradeValue to total
        total = total + gradeValue;
        // add 1 to gradeCounter
        gradeCounter = gradeCounter + 1;
        // prompt for input and read grade from user
        grade = window.prompt(
            "Enter Integer Grade, -1 to Quit:", "0" );
        // convert grade from a string to an integer
        gradeValue = parseInt( grade );