JavaScript also has dynamic types. That would mean the same variable used for holding different data types in JavaScript.Example                    var val;          val = "Amit";          document.write("String: "+val);          val = 20;          document.write("Number: "+val);          val = 40.90;          document.write("Number with decimals: "+val);                  

The onkeyup event triggers when a key is released.ExampleYou can try to run the following code to learn how to work with onkeyup event in JavaScript −                                         Enter subject below in upper case and see what happpens.          

The onsubmit event is an event that occurs when you try to submit a form. You can put your form validation against this event type. The following example shows how to use onsubmit. Here we are calling a validate() function before submitting a form data to the web server. If validate() function returns true, the form will be submitted, otherwise, it'll not submit the data.ExampleThe following example is a code snippet showing the usage of the onsubmit event −                                                  .......                    

The onkeypress event triggers when a key is pressed and released. You can try to run the following code to learn how to work with onkeypress event in JavaScript −Example                                            

The onkeydown event triggers when a key is pressed. You can try to run the following code to learn how to work with an onkeydown event in JavaScript −Example                                            

The onmouseup event triggers when a mouse button is released.ExampleYou can try to run the following code to learn how to work with onmouseup event in JavaScript −                                         This is demo text for mouseup event.    

It is an event that triggers when the mouse pointer moves out of an element.ExampleYou can try to run the following code to learn how to work with onmouseout event in JavaScript −                                         This is demo text for mouseover event.    

The onmouseover event triggers when the mouse pointer moves over an element.ExampleYou can try to run the following code to learn how to work with onmouseover event in JavaScript −                                         This is demo text for mouseover event.    

The onmousemove event triggers when the mouse pointer moves.ExampleYou can try to run the following code to learn how to work with onmousemove event in JavaScript −                                         This is demo text for mousemove event.    

The onmouseenter event triggers when after the mouse hover is moved out.ExampleYou can try to run the following code to learn how to work with an onmouseleave event in JavaScript −                                         This is demo text for mouseleave event.