var code;
function createCode() {
    code = new Array();
    var codeLength = 4;
    var checkCode = document.getElementById("checkCode");
    checkCode.value = "";
    var selectChar = new Array(2, 3, 4, 5, 6, 7, 8, 9, 'A', 'B', 'C', 'D',
            'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R',
            'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');

    for (var i = 0; i < codeLength; i++) {
        var charIndex = Math.floor(Math.random() * 32);
        code += selectChar[charIndex];
    }
    if (code.length != codeLength) {
        createCode();
    }
    checkCode.value = code;
};

function validatecode() {
    var verifyCode = document.getElementById("verifyCode").value.toUpperCase();
    var checkCode = document.getElementById("checkCode").value;
    if (verifyCode == null | verifyCode != checkCode) {
        alert("验证码输入错误！"); 
        return false;
    } else {
        return true;
    }
}

