var phone = document.getElementById("phone");

var tip = document.getElementById("tip");

function userNameOk(phone, tip) {

phone.onfocus = function () {

tip.innerHTML = "请输入11位手机号码";

tip.className = "black";

}

}

userNameOk(phone, tip);

function userNameBad(phone,tip) {

phone.onblur = function () {

var phoneVal = phone.value;

if (isNaN(phoneVal) == false && phoneVal.length == 11) {

tip.innerHTML = "输入正确";

tip.className = "green";

} else {

tip.innerHTML = "请输入11位数字";

tip.className = "red";

}

}

}

userNameBad(phone,tip);