I'm curious how i, with the following jQuery plugin code im writing at the bottom of this question, could implement key bos. How it's working so far is it allows a user to create key mands simply by doing a normal jQuery like syntax and provide an event for the key mand, like so:
$(window).jkey('a',function(){
alert('you pressed the a key!');
});
or
$(window).jkey('b c d',function(){
alert('you pressed either the b, c, or d key!');
});
and lastly what i want is the ability to do, but can't figure out:
$(window).jkey('alt+n',function(){
alert('you pressed alt+n!');
});
I know how to do this outside of the plugin (on keyup set a var false and on keydown set the var true and check if the var is true when you press the other key), but i don't know how to do this when you dont know what keys are going to be pressed and how many. How do I add this support? I want to be able to allow them to do things like alt+shift+a or a+s+d+f if they wanted. I just can't get my head around how to implement this. Any ideas?
I'm going to release this as an open source plugin and i'd love to give whoever gives me the right, working, answer some credit on the blog post and in the code it's self. Thanks in advance!
(function($) {
$.fn.jkey = function(keyCombo,callback) {
if(keyCombo.indexOf(' ') > -1){ //If multiple keys are selected
var keySplit = keyCombo.split(' ');
}
else{ //Else just store this single key
var keySplit = [keyCombo];
}
for(x in keySplit){ //For each key in the array...
if(keySplit[x].indexOf('+') > -1){
//Key selection by user is a key bo... what now?
}
else{
//Otherwise, it's just a normal, single key mand
}
switch(keySplit[x]){
case 'a':
keySplit[x] = 65;
break;
case 'b':
keySplit[x] = 66;
break;
case 'c':
keySplit[x] = 67;
break;
//And so on for all the rest of the keys
}
}
return this.each(function() {
$this = $(this);
$this.keydown(function(e){
if($.inArray(e.keyCode, keySplit) > -1){ //If the key the user pressed is matched with any key the developer set a key code with...
if(typeof callback == 'function'){ //and they provided a callback function
callback(); //trigger call back and...
e.preventDefault(); //cancel the normal
}
}
});
});
}
})(jQuery);
I'm curious how i, with the following jQuery plugin code im writing at the bottom of this question, could implement key bos. How it's working so far is it allows a user to create key mands simply by doing a normal jQuery like syntax and provide an event for the key mand, like so:
$(window).jkey('a',function(){
alert('you pressed the a key!');
});
or
$(window).jkey('b c d',function(){
alert('you pressed either the b, c, or d key!');
});
and lastly what i want is the ability to do, but can't figure out:
$(window).jkey('alt+n',function(){
alert('you pressed alt+n!');
});
I know how to do this outside of the plugin (on keyup set a var false and on keydown set the var true and check if the var is true when you press the other key), but i don't know how to do this when you dont know what keys are going to be pressed and how many. How do I add this support? I want to be able to allow them to do things like alt+shift+a or a+s+d+f if they wanted. I just can't get my head around how to implement this. Any ideas?
I'm going to release this as an open source plugin and i'd love to give whoever gives me the right, working, answer some credit on the blog post and in the code it's self. Thanks in advance!
(function($) {
$.fn.jkey = function(keyCombo,callback) {
if(keyCombo.indexOf(' ') > -1){ //If multiple keys are selected
var keySplit = keyCombo.split(' ');
}
else{ //Else just store this single key
var keySplit = [keyCombo];
}
for(x in keySplit){ //For each key in the array...
if(keySplit[x].indexOf('+') > -1){
//Key selection by user is a key bo... what now?
}
else{
//Otherwise, it's just a normal, single key mand
}
switch(keySplit[x]){
case 'a':
keySplit[x] = 65;
break;
case 'b':
keySplit[x] = 66;
break;
case 'c':
keySplit[x] = 67;
break;
//And so on for all the rest of the keys
}
}
return this.each(function() {
$this = $(this);
$this.keydown(function(e){
if($.inArray(e.keyCode, keySplit) > -1){ //If the key the user pressed is matched with any key the developer set a key code with...
if(typeof callback == 'function'){ //and they provided a callback function
callback(); //trigger call back and...
e.preventDefault(); //cancel the normal
}
}
});
});
}
})(jQuery);
4 Answers
Reset to default 5Use keypress instead of keyup/keydown because the latter two do not accurately protray the keycode (reference, see last paragraph). You can reference the altKey ctrlKey and shiftKey boolean properties of the event object in this case...
$(document).keypress(function(e) {
var key = String.fromCharCode(e.which);
var alt = e.altKey;
var ctrl = e.ctrlKey
var shift = e.shiftKey;
alert("Key:" + key + "\nAlt:" + alt + "\nCtrl:" + ctrl + "\nShift:" + shift);
});
Also, you can use String.fromCharCode to translate the key code to an actual letter.
You can't trap multiple keys aside from binations with Ctrl, Alt, and Shift. You simply can't do it in a single event. So throw the a+s+d+f idea out the window.
Note: Obviously there are certain key binations that are used by the browser. For instance, Alt + F usually brings up the File menu in Windows. Ctrl + N usually launches a new window/tab. Do not attempt to override any of these binations.
Here's a live demo for your testing pleasure.
Here's what I came up with. Essentially what I did was created a JSON object that stores all the key codes. I then replace all the provided keys with the codes. If the keys are using the '+' to make a key bo, I then create an array of the codes out of it.
We then create another array that stores all the keys that are being pressed (keyDown add the item, keyUp removes it). On keyDown, we check if it's a single key mand or bo. If it's a bo, we check it against all the currently active key presses. If they all match, we execute the callback.
This will work with any number of key bos. Only time I saw that it wasn't working is when you use the 'alert()' to display a message on the key bo because it will no longer remove the items from the active key press array.
(function($) {
$.fn.jkey = function(keyCombo,callback) {
// Save the key codes to JSON object
var keyCodes = {
'a' : 65,
'b' : 66,
'c' : 67,
'alt' : 18
};
var x = '';
var y = '';
if(keyCombo.indexOf(' ') > -1){ //If multiple keys are selected
var keySplit = keyCombo.split(' ');
}
else{ //Else just store this single key
var keySplit = [keyCombo];
}
for(x in keySplit){ //For each key in the array...
if(keySplit[x].indexOf('+') > -1){
//Key selection by user is a key bo
// Create a bo array and split the key bo
var bo = Array();
var boSplit = keySplit[x].split('+');
// Save the key codes for each element in the key bo
for(y in boSplit){
bo[y] = keyCodes[ boSplit[y] ];
}
keySplit[x] = bo;
} else {
//Otherwise, it's just a normal, single key mand
keySplit[x] = keyCodes[ keySplit[x] ];
}
}
return this.each(function() {
$this = $(this);
// Create active keys array
// This array will store all the keys that are currently being pressed
var activeKeys = Array();
$this.keydown(function(e){
// Save the current key press
activeKeys[ e.keyCode ] = e.keyCode;
if($.inArray(e.keyCode, keySplit) > -1){ // If the key the user pressed is matched with any key the developer set a key code with...
if(typeof callback == 'function'){ //and they provided a callback function
callback(); //trigger call back and...
e.preventDefault(); //cancel the normal
}
} else { // Else, the key did not match which means it's either a key bo or just dosn't exist
// Check if the individual items in the key bo match what was pressed
for(x in keySplit){
if($.inArray(e.keyCode, keySplit[x]) > -1){
// Initiate the active variable
var active = 'unchecked';
// All the individual keys in the bo with the keys that are currently being pressed
for(y in keySplit[x]) {
if(active != false) {
if($.inArray(keySplit[x][y], activeKeys) > -1){
active = true;
} else {
active = false;
}
}
}
// If all the keys in the bo are being pressed, active will equal true
if(active === true){
if(typeof callback == 'function'){ //and they provided a callback function
callback(); //trigger call back and...
e.preventDefault(); //cancel the normal
}
}
}
}
} // end of if in array
}).keyup(function(e) {
// Remove the current key press
activeKeys[ e.keyCode ] = '';
});
});
}
})(jQuery);
This is just a shot in the dark but maybe it'll help you down the right path.
If it's possible to have that function recognize a hexadecimal value for the key that you entered instead of the literal key (such as 0x6E for the letter 'n'), you could derive what "alt+n" translates to in hex and have the function look out for that value.
If you're looking for something that will let a user easily enter and define key bos using a plain input box, I wrote a plugin that does it for you: http://suan.github./jquery-keybinator/