javascript - allow empty input in jquery validation engine

Question

I am having this issue where I want an INPUT field to be just NUMBERS or EMPTY. If a user chooses to add a phone number or leave it blank if they don't want to.

I tried using this, but it requires a phone number if it's empty:

 "onlyNumberSp": {
                "regex": /^[0-9\ ]+$/,
                "alertText": "* Numbers only"
            },

Thank you

Answer 1

/^[0-9]*$/允许任意数量的数字，包括一个都没有（= 空字符串）。

如果您想保留空格，请使用/^[0-9 ]*$/（无需转义空格字符）。