我哪錯(cuò)了？
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8"/>
<title></title>
<script>
window.onload=function ()
{
?var oTxt1=document.getElementById('txt1');
?var oTxt2=document.getElementById('txt2');
?var oBtn=document.getElementById('btn1');
? ? oBtn.onclick=function ()
? { ?
?
? alert(oTxt1.value+oTxt2.value)
? ?
? }
}
</script>
</head>
<body>
<input class="txt1" type="text"/>
<input ?class="txt2" type="text"/>
<input id="btn1" type="button" value="求和"/>?
</body>
</html>
2016-12-14
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8"/>
<title></title>
<script>
window.onload=function ()
{
?var oTxt1=document.getElementById('txt1');
?var oTxt2=document.getElementById('txt2');
?var oBtn=document.getElementById('btn1');
? ? oBtn.onclick=function ()
? { ?
?
? alert(oTxt1.value+oTxt2.value)
? ?
? }
}
</script>
</head>
<body>
<input id="txt1" type="text"/>
<input ?id="txt2" type="text"/>
<input id="btn1" type="button" value="求和"/>?
</body>
</html>