javascript - Uncaught ReferenceError : Invalid left-hand side in assignment error

Question

我收到以下错误:

"Uncaught ReferenceError: Invalid left-hand side in assignment"

来自这段代码:

if (!oPrismaticMaterial = "") {
    for (var i = 0; i < oPrismaticMaterial.length; i++) {
        if (oPrismaticMaterial[i].checked) {
            oPrismaticMaterial[i].checked = true;
            radioChecked = true;
            break;
        }
    }
    if (!radioChecked) {
        bValidated = false;
        sErrorMessage += "Please select grades and metal\n";
    }
}

Answer 1

您应该在 if 语句中使用 != 而不是 =。

==是比较等于，!=是比较不等于，=是赋值。

因此你需要改变你的 if 语句:

if (!oPrismaticMaterial = "")

到

if (oPrismaticMaterial != "")