<head>.red{border:1px solid red;}</head><body>姓名：<input type="text"><span></span></body><script type="text/javascript"> var name=document.getElementsByTagName("Input")[0]; var tip=document.getElementsByTagName("span")[0]; function onfocusFn(){ if(this.value==""){ tip.innerHTML="请输入您的姓名"; }else{ tip.value=""; } } function onblurFn(){ if(this.value==""){ tip.innerHTML="用户名不能为空"; this.style.className="red"; }else{ tip.value=""; this.removeAttribute("class"); } } name.onfocus=onfocusFn; name.onblur=onblurFn;</script>请指教哪里出错了，好烦啊。。。速速帮忙解答。
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码农2号
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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.red{border:1px solid red;}
</style>
</head>
<body>
姓名：<input type="text" id="inp"><span></span>
<script type="text/javascript">
// var name=document.getElementsByTagName("input")[0];
var inp=document.getElementById('inp')
var tip=document.getElementsByTagName("span")[0];
function onfocusFn(){
if(this.value==""){
tip.innerHTML="请输入您的姓名";
}else{
tip.innerHTML="";
}
}
function onblurFn(){
if(this.value==""){
tip.innerHTML="用户名不能为空";
this.classList.add('red');
}else{
tip.innerHTML="";
this.classList.remove('red');
}
}
inp.onfocus=onfocusFn;
inp.onblur=onblurFn;
</script>
</body>
</html>添加回答
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