例//row=5 col=5
var str = "<table>"
var row = 1
while (row < 6) {
str += "<tr>"
var col = 1
while (col < 6) {
str += "<td>" + row + "</td>"
col++
}
str += "</tr>"
row++
}
str += "</table>"
document.body.innerHTML += str
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
td {
width: 20px
height: 10px
border: 1px solid #000
}
</style>
</head>
<body>
<script>
//乘法表
var str = "<table>"
var row = 1
while (row < 10) {
str += "<tr>"
var col = 1
//让后面的值小于等于前面得值
while (col <= row) {
str += "<td>" + row + "*" + col + "=" + row * col + "</td>"
col++
}
str += "</tr>"
row++
}
str += "</table>"
document.body.innerHTML += str
</script>
</body>
</html>
具体代码写法如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
document.write("<table>") //文档中插入table标签，用于显示99乘法表
for(var x=9x>=1x--){ //倒立乘法表，故从9开始for循环逐1减小到等于1
document.write("<tr>") //插入行标签
for(var y=1y<=xy++){ //从1开始循环，乘到等于该行数
document.write("<td>"+y+"*"+x+"</td>")
//插入列标签，显示乘法表的每一项
}
document.write("</tr>") //行标签闭合
}
document.write("</table>") //table标签闭合
</script>
</body>
</html>
2.最终效果如下图所示：
3.思路：
倒立的99乘法表，横向看，乘数从9开始递减到1，纵向看，被乘数是1开始递增到等于 乘数。
