If not, use a good system validation and provide clear error messages if invalid input is entered.

如果不行，使用一个良好的校验系统并提供清晰的错误提示。

youdao

Specifies if invalid binary characters should be filtered or not from the file before importing. Be aware that applying this filter may remove some Unicode characters.

指定在导入前是否过滤文件中无效的二进制字符。

youdao

If any such provision is determined to be invalid or otherwise unenforceable, these rules shall be construed in accordance with their terms as if the invalid or unenforceable provision was not contained therein.

CNN: Inside the Envelope

In the event that any such provision is determined to be invalid or otherwise unenforceable, these rules shall be construed in accordance with their terms as if the invalid or unenforceable provision was not contained therein.

WSJ: Blindfold Brackets 2013: Official Rules

What does a user see if he enters an invalid email address during registration?

FORBES: An E-commerce Guide For Entrepreneurs