<form name=form1 mothed=post>
<input type=text name=a value=abc onmouseover="alert(eval('form1.'+this.name).value);">
</form>
<input type=text name=a value=abc onmouseover="alert(eval('form1.'+this.name).value);">
</form>
<input type=text name=a value=abc onmouseover="document.form1.test.value=this.value;">
<input type="text" name="test" id="test">
</form>