1、默认打开手机数字输入键盘maxlength属性无效
<input class="ys1_" name="verificationCode" id="verificationCode" type="number" maxlength="4" placeholder="请输入验证码"/>
说明:设置type="number"
2、默认打开手机数字输入键盘,且maxlength="4"有效
<input class="ys1_" name="verificationCode" id="verificationCode" type="tel" maxlength="4" placeholder="请输入验证码"/>
说明:设置type="tel" maxlength="4"