detect caps lock status on page load (or similar)

In my r开发者_运维知识库esearch, I've found how to detect capslock when the caps key is pressed. However, I want to know the caps status even in cases when the key is not touched.

example: alert(ui.Keyboard.capslock) // would return true or false;

Thanks!

No, you cannot get the state of a keyboard button on page load. You have to analyze a keyCode of a keypress. That is the only way.

I've just come up with an alternative which will detect the state of caps lock and store it so that if the caps lock key is pressed a warning can be turned on and off. I'm only coding for chrome 45+ and ie9+ so there may need to be some adjustments for general use if that is your plan.

Here's my html:

<input type="text" id="pwd">
<p id="caps"></p>

And here's the js:

var LOGINPAGE = LOGINPAGE || {};
LOGINPAGE.CAPSdetect = {};
$(function() {
    LOGINPAGE.CAPSdetect.engage();
});

LOGINPAGE.CAPSdetect.isDetected = false;
LOGINPAGE.CAPSdetect.capsOn = false;

LOGINPAGE.CAPSdetect.engage = function() {
    $('#pwd').on('keypress', LOGINPAGE.CAPSdetect.shiftDetect);
    $(window).on('keydown', LOGINPAGE.CAPSdetect.capsDetect);
}

LOGINPAGE.CAPSdetect.shiftDetect = function(event) {
    var caps = $('#caps');
    var which = event.keyCode;
    var shift = event.shiftKey;
    var targ = event.target;
    if ((which >= 65 && which <= 90 && !shift) || (which >= 97 && which <= 122 && shift)) {
        caps.html('CAPS LOCK IS ON').css('color', 'crimson');
        LOGINPAGE.CAPSdetect.isDetected = true;
        LOGINPAGE.CAPSdetect.capsOn = true;
    } else if((which >= 65 && which <= 90 && shift) || (which >= 97 && which <= 122 && !shift)){
        caps.html('');
    }
}

LOGINPAGE.CAPSdetect.capsDetect = function(event) {
    if(event.keyCode === 20 && LOGINPAGE.CAPSdetect.isDetected) {
        LOGINPAGE.CAPSdetect.capsOn = (LOGINPAGE.CAPSdetect.capsOn)? false:true;
        if(LOGINPAGE.CAPSdetect.capsOn) {
            $('#caps').html('CAPS LOCK IS ON');
        } else {
            $('#caps').html('');
        }
    }
}

I'm using namespaces to avoid globals for isDetected and capsOn hence the LOGINPAGE.CAPSdetect. before some functions and variables. See this jsfiddle for no namespacing and to test it out.

Try this code:

    <script language="Javascript">
function capLock(e){
 kc = e.keyCode?e.keyCode:e.which;
 sk = e.shiftKey?e.shiftKey:((kc == 16)?true:false);
 if(((kc >= 65 && kc <= 90) && !sk)||((kc >= 97 && kc <= 122) && sk)){
  document.getElementById('divon').style.visibility = 'visible';
   document.getElementById('divoff').style.visibility = 'hidden';
 }else{
  document.getElementById('divon').style.visibility = 'hidden';
   document.getElementById('divoff').style.visibility = 'visible';
}
}
</script>
<input type="text" name="trackcaps" onkeypress="capLock(event)" />
<div id="divon" style="visibility:hidden">Caps Lock is on.</div>
<div id="divoff" style="visibility:hidden">Caps Lock is off.</div>