<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
window.onload = function() {
var oTxt1 = document.getElementById("txt1");
var oTxt2 = document.getElementById("txt2");
var oBtn = document.getElementById("btn1");
var n1 = parseFloat(oTxt1.value);
var n2 = parseFloat(oTxt2.value);
oBtn.onclick = function() {
alert(n1+n2);
};
};
</script>
</head>
<body>
<input type="text" id="txt1" >
<input type="text" id="txt2" >
<input type="button" id="btn1" value="=">
</body>
</html>my younger brother recently encountered a problem in self-study js,. I am a little confused today. I hope some great god can take a look at it
. var n1 = parseFloat(oTxt1.value);
var n2 = parseFloat(oTxt2.value); if the above two variables are defined outside oBtn.onclick = function () , NaN will pop up, but not if they are inside. Thank you!
