.myform select:required,
.myform input:required,
.myform textarea:required {
    background: #fff url(http://sandbox.runjs.cn/uploads/rs/216/0y89gzo2/star.jpg) no-repeat 99% center;
}
.myform select:required:valid,
.myform input:required:valid,
.myform textarea:required:valid {
    background: #fff url(http://sandbox.runjs.cn/uploads/rs/216/0y89gzo2/right.png) no-repeat 99% center;
    box-shadow: 0 0 5px #5cd053;
    border-color: #28921f;
}
.myform select:focus:invalid,
.myform input:focus:invalid,
.myform textarea:focus:invalid {
    background: #fff url(http://sandbox.runjs.cn/uploads/rs/216/0y89gzo2/error.png) no-repeat 99% center;
    box-shadow: 0 0 5px #d45252;
    border-color: #b03535
}

oninvalid="this.setCustomValidity('请输入正确的号码');" oninput="setCustomValidity('')"

function checkPassword() {
    var pass1 = document.getElementById("Password");
    var pass2 = document.getElementById("Repassword");

    if (pass1.value != pass2.value)
        pass2.setCustomValidity("两次输入的密码不匹配");
    else
        pass2.setCustomValidity("");
}

::-webkit-validation-bubble { min-width:152px; margin-top: -1px;}
::-webkit-validation-bubble-arrow { border: 1px solid #F7CE39; background: #FFFBC7; /* position:relative; */ top: 4px; left: 0px; }
::-webkit-validation-bubble-arrow-clipper { text-align: center; }
::-webkit-validation-bubble-heading { color: #444; }
::-webkit-validation-bubble-message { border: 1px solid #F7CE39; background: #FFFBC7; border-radius: 3px; }
::-webkit-validation-bubble-text-block { font-size: 12px; }

<form>
    <input required>
    <button>Submit</button>
</form>
<script>
    document.querySelector( "input" ).addEventListener( "invalid",
        function( event ) {
            event.preventDefault();
        });
</script>

function replaceValidationUI( form ) {
    //阻止气泡
    form.addEventListener( "invalid", function( event ) {
        event.preventDefault();
    }, true );
    // 支持Safari, iOS Safari, Android 浏览器
    // 默认提交表格
    form.addEventListener( "submit", function( event ) {
        if ( !this.checkValidity() ) {
            event.preventDefault();
        }
    });
    // 新增错误提示的容器
    form.insertAdjacentHTML( "afterbegin", "<ul class='error-messages'></ul>" );
    var submitButton = form.querySelector( "button:not([type=button]), input[type=submit]" );
    submitButton.addEventListener( "click", function( event ) {
        var invalidFields = form.querySelectorAll( ":invalid" ),
            listHtml = "",
            errorMessages = form.querySelector( ".error-messages" ),
            label;
        for ( var i = 0; i < invalidFields.length; i++ ) {
            label = form.querySelector( "label[for=" + invalidFields[ i ].id + "]" );
            listHtml += "<li>" + 
                label.innerHTML +
                " " +
                invalidFields[ i ].validationMessage +
                "</li>";
        }
        // 把错误的信息放到错误容器里面
        errorMessages.innerHTML = listHtml;
        // 给第一个错误的input选中
        // 错误信息容器显示
        if ( invalidFields.length > 0 ) {
            invalidFields[ 0 ].focus();
            errorMessages.style.display = "block";
        }
    });
}
// 替换form中所有的验证UI
var forms = document.querySelectorAll( "form" );
for ( var i = 0; i < forms.length; i++ ) {
    replaceValidationUI( forms[ i ] );
}