Call by ID · Method: document.getElementById('yourId') · Uniqueness: IDs are intended to be unique within an HTML document. Each element should have a different ID. · Return Type: This method returns a single Element object, or null if no element with the specified ID is found. Call by Class Name · Method: document.getElementsByClassName('yourClassName') · Uniqueness: Class names are not unique; multiple HTML elements can share the same class name. · Return Type: This method returns a live HTML Collection of elements that have the specified class name. Even if only one element ...