abstract：<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0">&
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script src="jq_3.3.1_mi.js"></script>
<title>Document</title>
<style>
body{font-size: 12px;}
.box{width: 600px;height: 180px;border:10px solid pink; margin: 0px auto;padding:10px; }
img{float: left;}
.box1{float: left;margin-left: 255px;width: 150px;height: 24px;text-align: right;font-size: 14px;color: #888;}
.box1 span{font-size: 16px;font-weight: bold;}
#text{width:580px;height: 100px;border: 1px solid #ccc;margin-top: 5px;resize: none;padding: 10px}
.box #sp1,#sp2,#sp3,#sp4,#sp5,#sp6{float: left;width: 30px;height: 32px;line-height: 32px;padding-left: 26px;}
#sp1{background: url(images/an5.png) no-repeat left center;}
#sp2{background: url(images/an4.png) no-repeat left center;}
#sp3{background: url(images/an3.png) no-repeat left center;}
#sp4{background: url(images/an2.png) no-repeat left center;}
#sp5{background: url(images/an1.png) no-repeat left center;width: 40px;}
#sp6{ margin-left: 158px;margin-right:15px;color: #888; }
#bt{float: left;width: 80px;height: 30px;border: none;background: #ffc09f;color: #fff;border-radius: 5px;}
</style>
</head>
<body>
<div class="box">
<img src="images/12.png" alt="">
<div class="box1">还可以输入<span id="number">140</span>字</div>
<textarea id="text"></textarea>
<span id="sp1">表情</span>
<span id="sp2">图片</span>
<span id="sp3">视频</span>
<span id="sp4">话题</span>
<span id="sp5">长微博</span>
<span id="sp6">公开</span>
<input type="button" value="发布" id="bt">
</div>
<!-- js写法 -->
<!-- <script>
window.onload=init;
function init(){
var number,text,bt,cha;//申明全局变量,在函数里可以使用
var text=document.getElementById("text");//先获取对象,再去获取属性
var number=document.getElementById("number");//先获取对象,再去获取属性
var bt=document.getElementById("bt");//先获取对象,再去获取属性
text.focus();
text.onkeyup=function(){
cha=140-text.value.length;
if(cha<=0){
number.innerHTML=cha;
number.style.color="red";
}else{
number.innerHTML=cha;
number.style.color="#888";
}
}
bt.onclick=function(){
if(cha<0){
alert('文字太多');
text.focus();
}else if(cha==140){
alert('请输入...');
text.focus();
}else if(text.value.length==0){
alert('请输入...');
text.focus();
}else{
window.location.href="http://www.baidu.com";
}
}
}
</script> -->
<!-- JQ写法 -->
<script>
$(function(){
var cha;
$('#text').focus();
$('#text').on('keyup',function(){
cha=140-$(this).val().length;
if(cha<=0){
$('#number').html(cha);
$('#number').css('color','red');
}else{
$('#number').html(cha);
$('#number').css('color','#888');
}
})
$('#bt').on('click',function(){
if(cha==140){
alert('请输入...');
$("#text").focus();
}else if(cha<0){
alert('字体太多...');
$("#text").focus();
}else if($("#text").val().length==0){
alert('请输入...');
$("#text").focus();
}else{
alert('发布成功...');
}
})
})
</script>
</body>
</html>
Correcting teacher：天蓬老师Correction time：2019-02-16 14:48:39
Teacher's summary：alert('请输入...');这类提示信息, 用占位符来显示会更好些吧