<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
//for循环九九乘法表
for(var a=0;a<=9;a++){
for(var b=1;b<=a;b++){
document .write(a+"*"+b+"="+(a*b)+" ");
}document.write("<br>");
}
document.write("<hr>");
//while循环九九乘法表
var c=0;
while(c<9){
c++;
var d=0;
while(d<c){
d++;
document.write(c+"*"+d+"="+(c*d)+" ")
}document.write("<br>");
}
document.write("<hr>");
//do-while循环
var e=0;
do{
e++;
var f=0;
do{
f++;
document.write(e+"*"+f+"="+(e*f)+" ")
}while(f<e)
document.write("<br>");}while(e<9)
</script>
</body>
</html>
具体效果图如下：