document.getElementById("myDIV").style.display = "none";
// 1) Hide an element based on its respective "ID"
document.getElementById("elemID").style.display = "none";
// 2) Hide an element based on its respective "class" name (this will hide multiple items if they share the same class!)
document.getElementsByClassName('elemClass').style.display = "none";
// 3) Hide an element based on its respective "HTML tag" (the below example detects <li> tags)
document.getElementsByTagName("LI").style.display = "none";
// 4) Hide an element based on its "Name attribute" (the below example detects element with the name "fname")
document.getElementsByName("fname").style.display = "none";