El evento DOMContentLoaded es disparado cuando el documento HTML ha sido completamente cargado y parseado, sin esperar hojas de estilo, images y subframes para finalizar la carga. Un evento muy diferente - load - debería ser usado solo para detectar una carga completa de la página. Es un error increíblemente popular usar load cuando DOMContentLoaded sería mucho más apropiado, así que úsalo con cuidado.
JavaScript síncrono pausa el parseo del DOM.
También hay mucho propósito general y bibliotecas autónomas que ofrecen métodos de navegador cruzado para detectar que el DOM está preparado.
If you want DOM to get parsed as fast as possible after the user had requested the page, some things you could do is turn your JavaScript asynchronous and to optimize loading of stylesheets which if used as usual, slow down page load due to being loaded in parallel, "stealing" traffic from the main html document.
| Property | Type | Description |
|---|---|---|
target {{readonlyInline}} |
{{domxref("EventTarget")}} | The event target (the topmost target in the DOM tree). |
type {{readonlyInline}} |
{{domxref("DOMString")}} | The type of event. |
bubbles {{readonlyInline}} |
{{jsxref("Boolean")}} | Whether the event normally bubbles or not. |
cancelable {{readonlyInline}} |
{{jsxref("Boolean")}} | Whether the event is cancellable or not. |
<script>
document.addEventListener("DOMContentLoaded", function(event) {
console.log("DOM fully loaded and parsed");
});
</script>
<script>
document.addEventListener("DOMContentLoaded", function(event) {
console.log("DOM fully loaded and parsed");
});
for(var i=0; i<1000000000; i++)
{} // this synchronous script is going to delay parsing of the DOM. So the DOMContentLoaded event is going to launch later.
</script>
{{CompatibilityTable}}
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | 1.0[1] | {{CompatGeckoDesktop("1")}}[1] | 9.0[2] | 9.0 | 3.1[1] |
| Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Basic support | {{CompatVersionUnknown}}[1] | {{CompatGeckoMobile("1")}}[1] | {{CompatUnknown}}[2] | {{CompatVersionUnknown}} | {{CompatVersionUnknown}}[1] |
[1] Bubbling for this event is supported by at least Gecko 1.9.2, Chrome 6, and Safari 4.
[2] Internet Explorer 8 supports the readystatechange event, which can be used to detect when the DOM is ready. In earlier versions of Internet Explorer, this state can be detected by repeatedly trying to execute document.documentElement.doScroll("left");, as this snippet will throw an error until the DOM is ready.