< !DOCTYPE html > <html lang = “en” > <head > <meta charset = “UTF-8” > <title > Document < /title>
</head > <style type = “text/css” > body {
background: #ccc;
}
label {
width: 100px;
display: inline – block;
}
span {
color: red;
}.container {
margin: 100px auto;
width: 400px;
padding: 50px;
line – height: 40px;
}
span {
margin – left: 30px;
font – size: 12px;
} < /style>
<body>
<div class=”container”>
<label>姓名不能為空</label > <input type = “text”id = “inp1″ > <span > </span><br/ > <label > phone不能為空 < /label><input type=”text” id=”inp2″><span></span > <br / ></div>
<script>
/ / 失去焦點後判斷使用者輸入是否為空
var inp1 = document.getElementById(“inp1”);
inp1.onblur = function() {
if (trim(this.value) === “”) {
alert(“輸入不能為空”);
} else {
alert(“輸入正確”);
}
};
function trim(str) {
return str.replace(/^s+|s+$/g, “”);
}
var inp2 = document.getElementById(“inp2”);
inp2.onblur = function(e) {
if (inp2.value == “4444”) {
alert(“正確”);
e.stopPropagation();
} else {
alert(“錯誤”)
}
}; < /script>
</body > </html>/