How to detect keyboard modifier (Ctrl or Shift) through JavaScript

Question

I have a function which detect max length. but the problem is that when the max length reached Ctrl+A combination does't work. How can I detect Ctrl+A combination through javascript.

This is my maxlength code.

if (event.keyCode==8 || event.keyCode==9 || event.keyCode==37 || event.keyCode==39 ){
        return true;
} else {            
        if((t.length)>=50) {    
            return false;
        }   
}

Answer 1

Check event.ctrlKey:

function keyHandler(event) {
    event = event || window.event;
    if(event.keyCode==65 && event.ctrlKey) {
        // ctrl+a was typed.
    }
}

Answer 2

key codes:

shift   16
ctrl    17
alt     18

your jQuery:

$(document).keydown(function (e) {
    if (e.keyCode == 18) {
        alert("ALT was pressed");
    }
});

JavaScript Madness: Keyboard Events