JavaScript 注释
JavaScript 注释可用于增强代码的可读性。
JavaScript 注释
可以添加注释来对 JavaScript 进行解释,或者提高其可读性。
单行的注释以 // 开始。
本例用单行注释来解释代码:
<script type="text/javascript">
// 这行代码输出标题:
document.write("<h1>This is a header</h1>");
// 这行代码输出段落:
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
</script>
// 这行代码输出标题:
document.write("<h1>This is a header</h1>");
// 这行代码输出段落:
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
</script>
JavaScript 多行注释
多行注释以 /* 开头,以 */ 结尾。
本例使用多行注释来解释代码:
<script type="text/javascript">
/*
下面的代码将输出
一个标题和两个段落
*/
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
</script>
/*
下面的代码将输出
一个标题和两个段落
*/
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
</script>
使用注释来防止执行
在本例中,我们用注释来阻止一行代码的执行:
<script type="text/javascript">
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
//document.write("<p>This is another paragraph</p>");
</script>
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
//document.write("<p>This is another paragraph</p>");
</script>
在本例中,我们用注释来阻止若干行代码的执行:
<script type="text/javascript">
/*
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
*/
</script>
/*
document.write("<h1>This is a header</h1>");
document.write("<p>This is a paragraph</p>");
document.write("<p>This is another paragraph</p>");
*/
</script>
在行末使用注释
在本例中,注释放置在语句的行末:
<script type="text/javascript">
document.write("Hello"); // 输出 "Hello"
document.write("World"); // 输出 "World"
</script>
document.write("Hello"); // 输出 "Hello"
document.write("World"); // 输出 "World"
</script>