JavaScript onkeypress event entry instance of of press or hold a keyboard key

2020-03-30 04:09:20
OfStack

JavaScript onkeypress event

The onkeypress event is triggered when a user presses or holds down a keyboard key.

Note: there is a slight difference between the onkeypress event and the (link: #) event. The onkeypress event does not handle the corresponding function key. After you specifically change the following example to an onkeydown event, type! Special characters like @#$can tell the difference.

prompt

Internet Explorer/Chrome USES event.keycode to fetch the pressed characters, while browsers such as Netscape/Firefox/Opera use event.which.

With the onkeypress event, only Numbers are allowed

Here's an example of using the onkeypress event to only allow users to enter Numbers in a form field:



<html>

<head>

<script>

function checkNumber(e)

{

    var keynum = window.event ? e.keyCode : e.which;

    //alert(keynum);

    var tip = document.getElementById("tip");

    if( (48<=keynum && keynum<=57) || keynum == 8 ){

        tip.innerHTML = "";

        return true;

    }else {

        tip.innerHTML = " Tip: enter only Numbers! ";

        return false;

    }

}   

</script>
</head>

<body>

<div> Please enter a number: <input type="text" onkeypress="return checkNumber(event);" />

<span id="tip"></span>

</div> 

</body>

</html>