index.htm
--------------------------
<form name=form1>
<input type=text name=text1>
<input type=button value=提交 onclick=window.open("main.htm","","")>
</form>main.htm------------------
<script>
function a(){
  form2.text2=window.opener.form1.text1.value;
}
</script><body onload=a()>
<form name=form2>
<input type=text name=text2>
</form>