我正在学习 JavaScript 并创建了一个倒数计时器 HTML 页面,其中 javascript 代码似乎返回了错误clientHeight
的正文。<div>
即使重新调整浏览器大小,我也想在正文的中间(垂直)显示我的倒计时 HTML 。请告诉我哪里错了。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>CountDown Timer</title>
<script type="text/javascript" >
function countdown(){
if(isNaN(document.getElementById("time").value))
{
document.getElementById("time").value = "Enter Valid Number";
return;
}
else
{
var i = document.getElementById("time").value;
var j=setInterval(function (){document.getElementById("new").innerHTML = i; i--;
if(i == -2){
document.getElementById("new").innerHTML = "Welcome";
clearInterval(j);}},1000);
}
}
function heightadjust(){
document.getElementById("main1").style.top = ((document.body.clientHeight/2)+54).toString() + "px";
}
</script>
</head>
<body onresize="heightadjust();" onload="heightadjust();">
<div style="margin:0 auto;" id="main1">
<center>
<div id="new" style="display:inline-block; padding:3px; font-size:60px; text-align:center; border:3px solid #000000; background-color:#CC3300; color:#FFFFFF; border-radius:6px;">Enter Time Below</div>
<br />
<input type="text" id="time" onfocus="this.value = ''; this.style.color = '#000000';" value="Enter Time here" style="color:#999999;" />
<button onclick="countdown();" >Start</button>
</center>
</div>
</body>
</html>
请给我一些提示,<div>
即使浏览器重新调整大小,如何保持垂直居中。