通过ul中的li来做九九乘法表
代码描述：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript-DOM（九九乘法表）</title>
</head>
<body>
<ul id="01">
</ul>
<script>
// var data = "";
/* for (var i = 0; i <= 9; i++) {
data += "<li>" + "这是第" + (i + 1) + "个数字" + "</li>";
} */
var data = "";
for (var i = 1; i <= 9; i++) {
data += "<li>";
for (var j = 1; j <= i; j++) {
data += j + "*" + i + "=" + (i * j) + "  ";
}
data += "</li>";
}
var x = document.getElementById("01");
x.innerHTML = data;
</script>
</body>
</html>
通过换行标签<br />来实现9*9乘法表
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript-DOM（九九乘法表）</title>
</head>
<body>
<div id="02">
</div>
<script>
var data = "";
for (var i = 1; i <= 9; i++) {
for (var j = 1; j <= i; j++) {
data += j + "*" + i + "=" + (i * j) + "  ";
}
data += "<br/>";
}
var x = document.getElementById("02");
x.innerHTML = data;
</script>
</body>
</html>