为什么我的Javascript警报没有显示？

Question

基本上，我试图通过PHP调用Javascript警报。 虽然，警报根本不起作用。

这是我的echo语句，可动态创建警报

echo "<script>alert('Uploaded file was not in the correct format\n\nExample of the correct format:\nquestion1,answer1,answer2,answer3,answer4\n
question2,answer1,answer2,answer3,answer4\nquestion3,answer1,answer2,answer3,answer4')</script>";

我发现，如果我将警报更改为此，则可以正常运行：

echo "<script>alert('Uploaded file was not in the correct format')</script>";

我相信换行符存在问题。

我将代码更改为此，但仍然没有运气：

echo "<script>alert('Uploaded file was not in the correct format\\nExample of the correct format:\\nquestion1,answer1,answer2,answer3,answer4\\n
question2,answer1,answer2,answer3,answer4\\nquestion3,answer1,answer2,answer3,answer4')</script>";

我收到以下错误：

SyntaxError: unterminated string literal
[Break On This Error]   

alert('Uploaded file was not in the correct format\nExample of the
------^

createplay.php (line 1, col 6)

有人对为什么这不起作用有任何建议吗？ 在网上进行了广泛搜索，找不到解决方案。

提前致谢！

Answer 1

您的\\n字符已被PHP的文字换行符代替。

字符串文字中未转义的文字换行符是JavaScript中的错误。

使用\\\\n将换行符转义序列发送到JavaScript。

Answer 2

尝试这样的事情：

    <?
    echo "<script>alert('Uploaded file was not in the correct format\\n\\nExample of the correct format:\\nquestion1,answer1,answer2,answer3,answer4\\n
   question2,answer1,answer2,answer3,answer4\\nquestion3,answer1,answer2,answer3,answer4')</script>";
    ?>

Answer 3

为了增加昆汀的答案，将单引号和双引号切换也能解决问题吗？

Answer 4

在\\ n和下一个字符之间插入一个空格，它将起作用。 我在您的系统上为您的代码尝试过，并且有效