【inner】
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'>
window.onload=function(){
var x=document.getElementById("mainTitle1").innerHTML;
document.getElementById("mainTitle").innerHTML=x;
}
</script>
</head>
<body>
<span id="mainTitle"></span>
<span style="display: none;" id="mainTitle1">Text Content</span>
</body>
</html>
