Question

I have the following function to get the value in a textarea with the id #posttext and to call a function to post something.

I do not want the user to be able to type in more than one line break in a row. How can I prevent that?

Here’s the code:

//Post something
$('#postDiv').on('keydown', '#posttext', function(e) {
if (e.which==13 && !e.shiftKey && $('#posttext').val()!=' Post something...') {

//This is what I tried to prevent a user from inserting more than one br in a row
var last = false;

var code = (e.keyCode ? e.keyCode : e.which);
if(code == 13) {
    if (last) { e.preventDefault(); }
    last=true;
}else{
    last=false;
}

//If not currently loading and enough text typed in, submit
if($('#imageFeedback').html()!=' | Loading...' && $('#posttext').val().length>15){

    //Say that it is loading
    $('#imageFeedback').css('color','black').css('font-weight','normal').html(' | Loading...');

    //Call function to post
    post($(this));
    return false;
}
}
});

Answer 1

It would be much better if you simply removed duplicate linebreaks later, e.g. with this regex: s/\n{2,}/\n/g

However, to do what you want, simply remove duplicate newlines onkeyup

$('#postDiv').on('keyup', '#posttext', function(e) {
    var val = $(this).val(),
        newval = val.replace(/\n{2,}/g, '\n');
    if(val != newval) {
        $(this).val(newval);
    }
});

Demo: http://jsfiddle.net/ThiefMaster/WJmhF/