SyntaxError:缺少；后为循环初始化器

Question

显示错误，如缺少；在for-循环之后。谢谢你的帮助。

 function checkAttempt(){
        var studentID = document.getElementById("studentID").value;
        var attempt = 0;

        for (attempt < 3 && studentID == localStorage.studentID){
            gradeTest;
            attempt = attempt + 1;
            localStorage.attempt = attempt;
            }       
        }

Answer 1

将for替换为while

function checkAttempt(){
    var studentID = document.getElementById("studentID").value;
    var attempt = 0;

    while (attempt < 3 && studentID == localStorage.studentID{
        gradeTest;
        attempt = attempt + 1;
        localStorage.attempt = attempt;
    }       
}