JavaScript pisz w identyfikatorze
document.getElementById("Yourid").innerHTML = "Hi WORLD!!"
MGT EDITS
document.getElementById("Yourid").innerHTML = "Hi WORLD!!"element.innerHTML = "<p>read this</p>" Change the inner HTML of an element
element.style.color = "blue"; Change the style of an HTML element
element.setAttribute(important, "true") Change the attribute value of an HTML element
element.important = "true" Change the attribute value of an HTML element