Javascript 哨兵计划是'；行不通

我是初学者，我的作业需要一些帮助。我不知道我做错了什么

我必须制作一个程序来读取从0到100和-1的考试分数集合，以停止处理。输入并验证分数。程序应计数并打印通过次数（>=50）和失败次数（0-50）。输入分数-1时，将显示通过次数和失败次数

<script>
var score = 0;
var passCount = 0;
var failCount = 0;

score = parseInt(prompt("Input score between 1-100, -1 to quit","0"));

while (score !< 0){
    if (score >= 50 || score <= 100){
    passCount = passCount + 1;
    alert ("You passed! Pass count = "+passCount+"Fail count = "+failCount);
    }
    else
    if (score<50){
    failCount = failCount + 1;
    alert ("You failed! Pass count = "+passCount+"Fail count = "+failCount);
    }
    else
    if (score > 100){
    alert ("Invalid number");
    }
    score = parseInt(prompt("Input score between 1-100, -1 to quit","0"));
}
document.write ("Total: Passes - "+passCount+"Fails "+failCount);
</script>

var得分=0；
var passCount=0；
var故障计数=0；
分数=parseInt（提示（“输入分数在1-100之间，-1表示退出”，“0”））；
while（分数！<0）{
如果（分数>=50 | |分数尝试改变你的状况
，而（分数！=-1）
要做的改变：

<script>
var score = 0;
var passCount = 0;
var failCount = 0;

score = parseInt(prompt("Input score between 1-100, -1 to quit","0"));

while (score >= 0){
    if (score >= 50 && score <= 100){
    passCount = passCount + 1;
    alert ("You passed! Pass count = "+passCount+"Fail count = "+failCount);
    }
    else
    if (score<50){
    failCount = failCount + 1;
    alert ("You failed! Pass count = "+passCount+"Fail count = "+failCount);
    }
    else
    if (score > 100){
    alert ("Invalid number");
    }
    score = parseInt(prompt("Input score between 1-100, -1 to quit","0"));
}
document.write ("Total: Passes - "+passCount+"Fails "+failCount);
</script>

while（分数>=0）

没有操作员
！=50
&&
分数=0）{
如果（分数>=50&&score谢谢！这就解决了它。：-）