<!--  head에 들어갈 문자 -->
<script language="javascript">
<!--
function go() {
  window.open(document.myform.mytext.value);
}
//-->
</script>

<!-- body에 들어갈 문자 -->
<form name=myform method=post action="javascript:go();">
<input type=text name=mytext value="http://" size=100>  
<input type=submit value=go>
</form>