<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/ xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Ejemplo de código JavaScript en el propio documento</title> <script type="text/javascript"> /**function limita(maximoCaracteres) { var elemento = document.getElementById("texto"); if(elemento.value.length >= maximoCaracteres ) { return false; } else { return true; } } **/ function comprueba(){ var cuadrotxt = document.getElementById("elemento"); alert ("value; "+cuadrotxt.value+"\n type: "+cuadrotxt.type+"\n name: "+cuadrotxt.name); alert ("elemento2: "+cuadrotxt.form.elemento2.value); } window.onload=function(){ if(document.forms.length > 0) { if(document.forms[0].elements.length > 0) { document.forms[0].elements[0].focus(); } } } </script> </head> <body> <form name="formulario" id="formulario" > <input type="number" name="elemento" id="elemento" /> <input type="number" name="elemento2" id="elemento2" /> <textarea id="texto" onkeypress="return limita(100);"></textarea> <input type="button" value="Enviar" onclick="this.value='enviando...';comprueba()"/> </form> </body> </html> <!--this.disabled=true;-->