Html模式属性匹配或允许空白

Question

我在html中有两个输入字段; phone_number和alt_phone_number。我希望alt_phone_number具有与phone_number相同的模式，并且附加选项为空白。有什么建议吗？

<input id="phone_number" maxlength="10" name="phone_number" pattern="[0-9]{7}|[0-9]{10}" placeholder="Phone Number" required="required" size="10" type="tel" />

<input id="alt_phone_number" maxlength="10" name="alt_phone_number" pattern="[0-9]{7}|[0-9]{10}" placeholder="Phone Number" required="required" size="10" type="tel" />

Answer 1

从alt_phone_number中删除“required”属性。

<input id="alt_phone_number" maxlength="10" name="alt_phone_number" pattern="[0-9]{7}|[0-9]{10}" placeholder="Phone Number"size="10" type="tel" />