js学习的关于微博输入字数限制的案例实战讲解和学习@
<!DOCTYPE html>
<html>
<head charset="utf-8"></head>
<title>微博输入</title>
<style type="text/css">
.box{width: 600px;height: 160px;border: 10px solid pink;margin-top: 0px auto;}
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: 590px;height: 100px;border: 1px solid #888;margin-top: 5px;}
#sp1{background: url(image/11.png) no-repeat left center;}
#sp2{background: url(image/33.png) no-repeat left center;}
#sp3{background: url(image/44.png) no-repeat left center;}
#sp4{background: url(image/55.png) no-repeat left center;}
#sp5{background: url(image/66.png) no-repeat left center;width: 40px;}
#sp6{margin-left: 160px;margin-right: 15px;color: #888;}
#bt1{float: right;width: 80px;height: 30px;border:none;background: #ffc09f;color: red;border-radius: 5px;}
</style>
<script type="text/javascript">
var text,number,m;
window.onload=function function_name(argument) {
text=document.getElementById('text')
number=document.getElementById("number")
bt=document.getElementById('bt')
text.onkeyup=function aa(){
m=140-text.value.length
if (m<0) {
number.style.color="red"
}else{
number.style.color="#888"
}
number.innerHTML=m
}
bt.onload=function(){
if (m==140) {
alert("你还没有输入!")
text.focus()
}else if (m<0) {
alert("你的字数太多,不可以发布!")
text.focus()
}else{
alert("发布成功!")
}
}
aa()
}
</script>
</head>
<body>
<div class="box">
<img src="image/12.png">
<div class="box1">还可以输入<span id="number"></span></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>
</body>
</html>
