function contarCaracteres(control, countfield, max) { if (control.value.length > max) control.value = control.value.substring(0, max); else countfield.value = max - control.value.length } function detectar() { try { request = new ActiveXObject("Msxml2.XMLHTTP") } catch (e) { try { request = new ActiveXObject("Microsoft.XMLHTTP") } catch (E) { request = false } } if (!request && typeof XMLHttpRequest != 'undefined') { try { request = new XMLHttpRequest() } catch (e) { request = false } } if (!request && window.createRequest) { try { request = window.createRequest() } catch (e) { request = false } } }