下面是我在课本上的一到习题！根据学生的等级评A B C D级。
<script language="javascript">
document.write("<font size='+1'>");
while(true){
var score=eval(prompt("Please input the score:",""));
if (score<0 || score>100){
document.writeln("The score should be between 0 to 100!");
continue;
}
if(score>89 && score<101){
document.writeln("The degree is: A");
}
else if (score>79 && score<90){
document.writeln("The degree is: B");
}
else if(score>69 && score<80){
document.writeln("The degree is: c");
}
else if(score>59 && score<70);{
document.writeln("The degree is: D");
}
else {
document.writeln("It is bad!");
}
answer = prompt("Do you want to input another student?","");
if(answer !="y"){
break;
}
}
document.write("终于可以休息了．．．<br>");
</script>

我仔细的检查过上面的代码好几次了，都没发现什么错误啊！但是浏览的时候就是空白页，什么提示框都没有，真奇怪，请指教吧！呵呵

呵呵,真是马虎,谢谢啦!
我觉得这个javascript不想vbscript,即使出错了好像不会给出提示.

break必须放在一个循环体内
最后的prompt如果回答是也没有返回到最前面,也就无法执行下去了.应该放在一个
while(true){
.....
}
里面


switch的用法也有问题



你第一次的代码只要去掉那个;就OK了

function do(){
var score=prompt("Please input the score:","")
switch(true){
case score>89 && score<101:
document.writeln("The degree is: A");
break;
case score>79 && score<90:
document.writeln("The degree is: B");
break;
case score>69 && score<80:
document.writeln("The degree is: C");
break;
case score>59 && score<70:
document.writeln("The degree is: D");
break;
case score<59:
document.writeln("The degree is: Bad");
break;
answer = prompt("Do you want to input another student?","");
if(answer !="y"){
return false;
}else{
do();
}
}
}

do();

var s = 1;
switch(s){
case 1:
document.write("1");
break
case 2:
document.write("2");
break;
}