成绩考评

<script language=javascript>

var score,grade;

score=parseFloat(prompt("请输入学生的成绩：","0"));

if(score>=90)

grade="优";

else

if(score>=80)

grade="良";

else

if(score>=70)

grade="中";

else

if(score>=60)

grade="及格";

else

grade="不及格";

alert("根据学生成绩："+score+"，评定为："+grade);

</script>