<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>js练习</title> </head> <body> <h2>1.使用递归算法计算n的阶乘:n!</h2> <script type="text/javascript"> function jieCheng(n){ if(n==1){ return 1; }else{ return n*jieCheng(n-1); } } document.write("5!="+jieCheng(5)+'</br>'); </script> <h2>2.输出1000-9999直接的所有回文。</h2> <script type="text/javascript"> function huiWen(m){ qianWei=Math.floor(m/1000); baiWei=Math.floor(m%1000/100); shiWei=Math.floor(m%100/10); geWei=m%10; if(qianWei==geWei&&baiWei==shiWei){ return m; }else{ return null; } } j=0; for(i=1000;i<=9999;i++){ result=huiWen(i); if(result!=null){ document.write(result+','); j++; if(j%10==0){ document.write('</br>'); } } } </script> <h2>3.利用循环函数输出字符*,构成一个圣诞树的形状。</h2> <script type="text/javascript"> function shengDanShu(z){ for(x=1;x<=z;x++){ for(y=1;y<=z-x;y++){ document.write(' '); } for(k=1;k<=2*x-1;k++){ document.write('*'); } document.write('</br>'); } } shengDanShu(6); </script> </body> </html>