Firefox keydown backspace issue

I'm building a terminal emulation and running into an issue with capturing backspace in Firefox. I'm able to nab the first backspace and remove the last character on the input at the prompt, but it won't persist and remove more than one character.

Actual website: http://term.qt.io/

Replication here: http://jsfiddle.net/BgtsE/1/

JavaScript code

function handleKeys(e){
    var evt = e || window.event;
    var key = evt.charCode || evt.keyCode;
    if(evt.type == "keydown")
    {
        curr_key = key;
        if(key == 8)
        {
            evt.preventDefault();
            if(0 < $('body').text().length)
                $('body').text($('body').text().slice(0,-1));
        }
    }
    else if(evt.type == "keypress")
    {
        if(97 <= key && key <= 122)
        {
            if(curr_key != key)
                $('body').append(String.fromCharCode(key));
        }
        else
            $('body').append(String.fromCharCode(key));
    }
}
$(function(){
    $('html').live({
        keydown:function(e){
            handleKeys(e);
        },
        keypress:function(e){
            handleKeys(e);
        }
    })
})

Try this: http://jsfiddle.net/NBZG8/1/

You'll need to handle backspace in both keydown and keypress to support Chrome and Firefox

function handleKeys(e){
    var evt = e || window.event;
    var key = evt.charCode || evt.keyCode;

    if (evt.type == "keydown") {
        curr_key = key;
        if(key == 8 && !$.browser.mozilla) {
            backspaceHandler(evt);
        }
    } else if (evt.type == "keypress") {
        if (key == 8) {
            backspaceHandler(evt);
        } else if (97 <= key && key <= 122) {
            if(curr_key != key) {
                $('body').append(String.fromCharCode(key));
            }
        } else {
            $('body').append(String.fromCharCode(key));
        }
    }
}

function backspaceHandler(evt) {
    evt.preventDefault();
    if(0 < $('body').text().length) {
        $('body').text($('body').text().slice(0,-1));
    }  
};

$(function(){
    $('html').live({
        keydown : handleKeys,
        keypress : handleKeys
    })
})

HMR

In firefox Windows 17.0.1 any value returned by $("selector").text() has an added new line character appended to the end. So the substring didn't work for me:

<html>
    <head>
        <title>test</title>
        <script src="jquery.js"></script>
        <script>
            $("document").ready(function(){
                console.log("body text seems to have a new line character");
                console.log(($('body').text()[5]=="\n"));
            });

            function handleKeys(e){
                var evt = e || window.event;
                var key = evt.charCode || evt.keyCode;
                if(evt.type == "keydown")
                {
                    curr_key = key;
                    if(key == 8)
                    {
                        evt.preventDefault();
                        if(0 < $('body').text().length)
                            // next line works, you might trim the \n if it's there at the end
                            //$('body').text($('body').text().slice(0,-2));
                            // this one didn't work for me
                             $('body').text($('body').text().substring(0,$('body').text().length-1)); 
                    }
                }
                else if(evt.type == "keypress")
                {
                    if(97 <= key && key <= 122)
                    {
                        if(curr_key != key)
                            $('body').append(String.fromCharCode(key));
                    }
                    else
                        $('body').append(String.fromCharCode(key));
                }
            }
            $(function(){
                $('html').live({
                    keydown:function(e){
                        handleKeys(e);
                    },
                    keypress:function(e){
                        handleKeys(e);
                    }
                })
            })
        </script>
    </head>
    <body>12345</body>
</html>

Steve

I had the same issue with keypress on mozilla. Thanks to this subject it solves my problem so I'll post my code if anyone try to do the same thing as me.
In my exemple I try to auto space when the user type two numbers, and it didn't work in Firefox so that's my code :

$(function() {

    $('#field1, #field2').on('keypress',function(event) {
        event = event || window.event;
        var charCode = event.keyCode || event.which,
            lgstring = $(this).val().length,
            trimstring;
        if(charCode === 8) {
            event.returnValue = false;
            if(event.preventDefault)
                event.preventDefault();
            if(0 < $(this).val().length) {
                $(this).val($(this).val().slice(0,-1));
            }  
        }
        else if(((charCode > 31) && (charCode < 48 || charCode > 57)) || lgstring >= 14) {
            event.returnValue = false;
            if(event.preventDefault)
                event.preventDefault();
        }
        else {
            trimstring = $(this).val().replace(/ /g,"");
            if((lgstring !== 0) && (trimstring.length % 2) === 0 ) {
                $(this).val($(this).val() + ' ');
            }
        }
    });

});

I noticed that Mozilla handle the backspace as a keypress where Chrome don't.

Sorry for my English I'm French

$('#id').keypress(function(e) {

if(e.charCode > 0 || e.keyCode === 8){
 if(e.keyCode === 8){
   return true;
 }else if((e.charCode !== 0) && ((e.charCode  > 57 && e.charCode  < 65)){
   return false;
   }
 }else if((e.keyCode !== 0) && ((e.keyCode  > 57 && e.keyCode  < 65)){
  return false;
 }
});

来源：https://stackoverflow.com/questions/14050086/firefox-keydown-backspace-issue

标签

javascript

jquery

events

firefox

keydown