DIV居中——不大不小的问题

<div style="border: 1 solid red;position: absolute;top:expression((this.parentElement.offsetHeight-this.offsetHeight)/2);left:expression((this.parentElement.offsetWidth-this.offsetWidth)/2);">我站在中央了<br>center</div>

</div>

<div style="border: 1 solid #C0C0C0;"><br><br><br><br><br><br><br><br>

<div style="border: 1 solid red;position: absolute;top:expression((this.parentElement.offsetHeight-this.offsetHeight)/2);left:expression((this.parentElement.offsetWidth-this.offsetWidth)/2);">我站在中央了<br>center</div>

</div>