resolvi fazer de uma maneira mais simples: a página abre no iframe, mas o script não localiza o conteúdo do iframe, só o da página em torno dele: <script language="JavaScript">
var NS4 = (document.layers); // Which browser?
var IE4 = (document.all);
var win = window; // window to search.
var n = 0;
function findInPage(str) {
var txt, i, found;
if (str == "")
return false;
// Find next occurance of the given string on the page, wrap around to the
// start of the page if necessary.
if (NS4) {
// Look for match starting at the current point. If not found, rewind
// back to the first match.
if (!win.find(str))
while(win.find(str, false, true))
n++;
else
n++;
// If not found in either direction, give message.
if (n == 0)
alert("Não Localizado");
}
if (IE4) {
txt = win.document.body.createTextRange();
// Find the nth match from the top of the page.
for (i = 0; i <= n && (found = txt.findText(str)) != false; i++) {
txt.moveStart("character", 1);
txt.moveEnd("textedit");
}
// If found, mark it and scroll it into view.
if (found) {
txt.moveStart("character", -1);
txt.findText(str);
txt.select();
txt.scrollIntoView();
n++;
}
// Otherwise, start over at the top of the page and find first match.
else {
if (n > 0) {
n = 0;
findInPage(str);
}
// Not found anywhere, give message.
else
alert("Não Localizado");
}
}
return false;
}
</script>
<center>
<form name="search" onSubmit="return findInPage(this.string.value);">
<input name="string" TYPE="SUBMIT" size=15 onChange="n = 0;" value="variável 1"></font>
</form>
<form name="search" onSubmit="return findInPage(this.string.value);">
<input name="string" TYPE="SUBMIT" size=15 onChange="n = 0;" value="variável 2"></font>
</form>
<form name="search" onSubmit="return findInPage(this.string.value);">
<input name="string" TYPE="SUBMIT" size=15 onChange="n = 0;" value="variável 3"></font>
</form>
<form name="search" onSubmit="return findInPage(this.string.value);">
<input name="string" TYPE="SUBMIT" size=15 onChange="n = 0;" value="variável 4"></font>
</form>
<form>
<IFRAME src="http://scriptbrasil.com.br" frameBorder="no" width="400" height="150" scrolling="auto"></IFRAME>
</form>