html
<div class="form-group"><input id="register-username" class="input-material" type="email" name="registerUsername" placeholder="请输入邮箱" ><div class="invalid-feedback">请输入正确的邮箱格式</div></div>
js部分。记得引用jquery.js文件
$("#register-username").change(function(){name=$("#register-username").val();var re=/^([a-zA-Z0-9]+[_|\_|\.]?)*[a-zA-Z0-9]+@([a-zA-Z0-9]+[_|\_|\.]?)*[a-zA-Z0-9]+\.[a-zA-Z]{2,3}$/if(!re.test(name)){$("#register-username").removeClass("form-control is-valid")$("#register-username").addClass("form-control is-invalid");flagName=false;}else{$("#register-username").removeClass("form-control is-invalid")$("#register-username").addClass("form-control is-valid");flagName=true;}})
