var a=1;
while(a<=9){
var b=1;
while(b<=a){
if(b==2&&(a==4||a==3)){
document.write(a+"*"+b+"="+b*a+" ");
}else{
document.write(a+"*"+b+"="+b*a+" ");
}
b++;
}
document.write("换行");
a++;
}