JavaScript functions can be automatically invoked on different events by registering them with body tag.
JavaScript can be called inside <body> tag of a web page. Mainly JavaScript functions are called on events like Loading a web page, Clicking on a button, Moving mouse, Focusing on an element, etc. For each of these events, there are defined methods and they are fired at that particular event. For example; onclick() is triggered on a mouse click event while onmouseover() is called when mouse moves over an element. But you can call JavaScript functions even without any event.
Available events for body tag are...
- ONCLICK : mouse button clicked
- ONDBLCLICK : mouse button double-clicked
- ONMOUSEDOWN : mouse button is pressed
- ONMOUSEOVER : mouse moved onto an element
- ONMOUSEMOVE : mouse moved over an element
- ONMOUSEOUT : mouse moved out of an element
- ONMOUSEUP : mouse button is released
- ONKEYPRESS : key pressed and released
- ONKEYDOWN : key pressed
- ONKEYUP : key released
- ONLOAD : document loaded completely
- ONUNLOAD : document unloaded
Calling a JavaScript method
At any of the above events, you can call any JavaScript function from your <body> tag. A JavaScript function named testAlert() can be called as below.
<body onload="testAlert();">
To call move than one JavaScript function, you have to write the function names separated by semi-colons ( ; ) as below.
<body onload="validate(); calculate(); submit();">
COMMENTS