Gracias a todos:
Saludos
Código PHP:
<html>
<head>
<script language="JavaScript">
function agrega(cLetra) {
document.frm.texto.value += cLetra;
}
</script>
<script>
//"Accept terms" form submission- By Dynamic Drive
//For full source code and more DHTML scripts,
// visit [url]http://www.dynamicdrive.com[/url]
//This credit MUST stay intact for use
var checkobj
function agreesubmit(el){
checkobj=el
if (document.all||document.getElementById){
for (i=0;i<checkobj.form.length;i++){ //hunt down submit button
var tempobj=checkobj.form.elements[i]
if(tempobj.type.toLowerCase()=="submit")
tempobj.disabled=!checkobj.checked
}
}
}
function defaultagree(el){
if (!document.all&&!document.getElementById){
if (window.checkobj&&checkobj.checked)
return true
else{
alert("Please read/accept terms to submit form")
return false
}
}
}
</script>
</head>
<body>
<form name="frm">
<input name="agreecheck" type="checkbox" name="btA" value="A" onClick="agrega('http://www.')" onClick="agreesubmit(this)">Recomienda
una pagina<br>
<input type="text" name="texto" disabled size="20">
</form>
<script>
//change two names below to your form's names
document.forms.frm.agreecheck.checked=false
</script>
</body>
</html>