代码如下：
<script LANGUAGE="JAVASCRIPT"> <!-- hide this script tag's contents from old browsers function ClearForm(form){ form.weight.value = ""; form.height.value = ""; form.bmi.value = ""; form.my_comment.value = ""; } function bmi(weight, height) { bmindx=weight/eval(height*height); return bmindx; } function checkform(form) { if (form.weight.value==null||form.weight.value.length==0 || form.height.value==null||form.height.value.length==0){ alert("\n哈哈！你比我还要疯，数字都不会输"); return false; } else if (parseFloat(form.height.value) <= 0|| parseFloat(form.height.value) >=500|| parseFloat(form.weight.value) <= 0|| parseFloat(form.weight.value) >=500){ alert("\n老河生产的这个机器可不是成能的 \n你输的天数字我头都大了 \n快改正一下，再测试一遍……"); ClearForm(form); return false; } return true; } function computeform(form) { if (checkform(form)) { yourbmi=Math.round(bmi(form.weight.value, form.height.value/100)); form.bmi.value=yourbmi; if (yourbmi >30) { form.my_comment.value="不要在闹了!!!哪有这种身材"; } else if (yourbmi >28 && yourbmi <=30) { form.my_comment.value="您是猪吗?"; } else if (yourbmi >23 && yourbmi <=28) { form.my_comment.value="两头猪也没有你这么重吧?"; } else if (yourbmi >21 && yourbmi <=23) { form.my_comment.value="我敢打赌，你一定经常抢吃的，不然不会偏胖"; } else if (yourbmi >=19 && yourbmi <=21) { form.my_comment.value="哇!!!您棒级了!是标准身材，你是不是女孩子，小心会有很多人爱上你喽"; } else if (yourbmi >=18 && yourbmi <19) { form.my_comment.value="朋友你是不是吃草的，很明显的营养不良?????"; } else if (yourbmi >=17 && yourbmi <18) { form.my_comment.value="这个不是火柴杆吗????"; } else if (yourbmi <17) { form.my_comment.value="按照生物学来说这种生物是不能生存的"; } } return; } // -- done hiding from old browsers --> </script> <form NAME="BMI" method="POST"> <div align="center"> <center> <table border="1" bordercolorlight="#808080" cellspacing="1" bordercolordark="#FFFFFF" bgcolor="#F0F0F0" width="613"> <tr> <td width="72"><div align="center"><center><p>体重 (kg) </div> </center></td> <td align="center" width="64"><div align="center"><center><p>身高(cm) </div> </center></td> <td align="center" width="55"><div align="center"><center><p>健康值 </div> </center></td> <td align="center" width="313"><div align="center"><center><p>电脑对您的评价 </div> </center></td> <td align="center" width="75"><input TYPE="reset" VALUE="取 消" onClick="ClearForm(this.form)"> </td> </tr> <tr align="center"> <td width="72"><input TYPE="TEXT" NAME="weight" SIZE="6" onFocus="this.form.weight.value=''"></td> <td width="64"><input TYPE="TEXT" NAME="height" SIZE="6" onFocus="this.form.height.value=''"></td> <td width="55"><input TYPE="TEXT" NAME="bmi" SIZE="5"></td> <td width="313"><input TYPE="TEXT" NAME="my_comment" size="40"></td> <td width="75"><input TYPE="button" VALUE="确 定" onClick="computeform(this.form)"></td> </tr> </table> </center> </div> <div align="center"><center><p>  </p> </center></div> </form>