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请先填写你的体重和身高");
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八戒，知道你在做什么吗？ \n\n体重单位为公斤(kg)，身高单位为厘米(cm) \n\n请重新填写你输入的值");
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="八戒，不要再闹了！！！";
}
else if (yourbmi >28 && yourbmi <=30) {
form.my_comment.value="您实在太肥了！阿门！";
}
else if (yourbmi >23 && yourbmi <=28) {
form.my_comment.value="太胖啦！减肥啦！";
}
else if (yourbmi >21 && yourbmi <=23) {
form.my_comment.value="您现在是偏胖，应该注意饮食！";
}
else if (yourbmi >=19 && yourbmi <=21) {
form.my_comment.value="哇！您太苗条了！是标准身材";
}
else if (yourbmi >=18 && yourbmi <19) {
form.my_comment.value="您是不是营养不良？？";
}
else if (yourbmi >=17 && yourbmi <18) {
form.my_comment.value="这个不是骨头吗？？";
}
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;
}