1、编写一个小型的计算器
实例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>小型简易计算器</title>
<style type="text/css">
.box {
width: 500px;
height: 200px;
background-color: #efefef;
border: 1px solid lightgray;
text-align: center;
margin: 20px auto;
color: #636363;
border-radius: 15px;
box-shadow: 2px 2px 2px #999;
}
table {
margin: auto;
}
td {
width: 100px;
height: 30px;
padding: 5px 10px;
}
input, select {
width: 100%;
height:100%;
border:none;
text-align: left;
padding-left: 15px;
border-radius: 15px;
}
button {
width: 100%;
height: 100%;
border: none;
background-color: skyblue;
color: white;
border-radius: 13px;
}
button:hover {
cursor: pointer;
background-color: coral;
width: 105%;
height: 105%;
}
</style>
</head>
<body>
<div class="box">
<h2>小小计算器</h2>
<form>
<table>
<tr>
<td><input type="text" name="opt1" placeholder="操作数1" autofocus></td>
<td>
<select name="option">
<option value="null">运算符</option>
<option value="add"> + </option>
<option value="sub"> - </option>
<option value="mul"> * </option>
<option value="div"> / </option>
</select>
</td>
<td><input type="text" name="opt2" placeholder="操作数2"></td>
<td><button type="button">计算</button></td>
</tr>
<tr>
<td colspan="2" align="right"><h3>结果:</h3></td>
<td colspan="2" align="left"><h3 id="result"></h3></td>
</tr>
</table>
</form>
</div>
<script type="text/javascript">
//1.获取操作数,按钮与结果占位符
var opt1 = document.getElementsByName('opt1')[0];
var opt2 = document.getElementsByName('opt2')[0];
var opt = document.getElementsByName('option')[0];
var btn = document.getElementsByTagName('button')[0];
var result = document.getElementById('result');
//2.给按钮添加事件,执行计算操作
btn.onclick = function(){
var data1 = 0;
var data2 = 0;
if (opt1.value.length === 0 ) {
alert('第一个操作数不能为空');
opt1.focus();
return false;
} else if (isNaN(opt1.value)) {
alert('第一个操作数必须为数字');
opt1.focus();
return false;
} else if (opt2.value.length === 0) {
alert('第二个操作数不能为空');
opt2.focus();
return false;
} else if (isNaN(opt2.value)) {
alert('第二个操作数必须为数字')
opt2.focus();
return false;
} else {
data1 = parseFloat(opt1.value);
data2 = parseFloat(opt2.value);
}
var option = opt.value;
var temp = 0;
var flag = '';
switch (option){
case 'null':
alert("请选择操作类型");
opt.focus();
return false;
case 'add':
flag = '+';
temp = data1 + data2;
break;
case 'sub':
flag = '-';
temp = data1 - data2;
break;
case 'mul':
flag = '*';
temp = data1 * data2;
break;
case 'div':
flag = '/';
if (data2 === 0) {
alert('除数不能为0,请重新输入');
opt2.focus();
return false;
} else {
temp = data1 / data2;
//保留小数点2位
temp = Math.round(temp * 100) / 100;
}
break
}
var str = '<span style="color:coral">';
str += data1+' '+flag+' '+data2 + ' = ' + temp ;
str += '</span>';
result.innerHTML = str;
}
</script>
</body>
</html>运行实例 »
点击 "运行实例" 按钮查看在线实例
2、编写一个在线客服功能
实例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>在线客服功能</title>
<style type="text/css">
div:nth-child(1) {
width: 450px;
height: 650px;
background-color: lightskyblue;
margin: 30px auto;
color: #333;
box-shadow: 2px 2px 2px #808080
}
h2 {
text-align: center;
margin-bottom: -10px;
}
div:nth-child(2) {
width: 400px;
height: 500px;
border: 4px double green;
background-color: #efefef;
margin: 20px auto 10px;
}
ul {
list-style: none;
line-height: 2em;
overflow: hidden;
padding: 15px;
}
table {
width: 90%;
height:80px;
margin: auto;
}
textarea{
border: none;
resize: none;
background-color: lightyellow;
}
button {
width: 60px;
height: 40px;
background-color: seagreen;
color: white;
border: none;
}
button:hover {
cursor: pointer;
background-color: orange;
}
li {
overflow: auto;
/*清除浮动*/
}
</style>
</head>
<body>
<div>
<h2>在线客服</h2>
<div contenteditable="true">
<ul>
<li></li>
</ul>
</div>
<table>
<tr>
<td align="right"><textarea cols="50" rows="4" name="text" autofocus></textarea></td>
<td align="left"><button type=button>发送</button></td>
</tr>
</table>
</div>
<script type="text/javascript">
//获取到页面中的按钮,文本域,对话内容区
var btn = document.getElementsByTagName('button')[0];
var text = document.getElementsByName('text')[0];
var list = document.getElementsByTagName('ul')[0];
var sum = 0;
//添加按钮点击事件,获取用户数据并推送到对话窗口中
btn.onclick = function () {
//获取用户提交的内容
if (text.value.length === 0) {
alert('小老弟:你还想发空内容？');
return false;
}
var userComment = text.value;
//立即清空用户信息区
text.value = '';
//创建一个新节点li
var li = document.createElement('li');
li.innerHTML = userComment;
var userPic = '<img src="http://img1.gtimg.com/sports/pics/hv1/24/127/1665/108299034.jpg" width="30" style="border-radius:50%">';
li.innerHTML = userPic+userComment;
//将新节点插入到对话列表中
list.appendChild(li);
sum += 1;
setTimeout(function(){
var info = ['一天到晚就会喊我，你烦不烦呀?','除了我不卖，只要钱够啥都卖','找我干哈，有事快说！'];
var temp = info[Math.floor(Math.random()*3)]; //获取随机的内容
var reply = document.createElement('li'); /*创建新元素用来保存回复内容*/
var kefuPic = '<img src="http://tx.haiqq.com/uploads/allimg/150327/211551I17-12.jpg" width="30" style="border-radius:50%;float: right;">';
reply.innerHTML = kefuPic + '<span style="color:pink;float: right;">'+temp+'</span>';
list.appendChild(reply); //将回复内容添加到窗口中
sum += 1; // 回复内容计数加1
},1000);
//如果回复内容大于10条则清空聊天窗口
if (sum > 10) {
list.innerHTML = ''; //清空内容
sum = 0; // 清空计数器
}
}
</script>
</body>
</html>运行实例 »
点击 "运行实例" 按钮查看在线实例