通过JavaScript添加后从文本区域读取时保留标签

Question

I'm having a problem with preserving tab characters when reading the value of a textarea. I'm adding the tabs as follows:

$("#code-editor").keydown(function (e) {
    if (e.keyCode === 9) { // tab was pressed
        // get caret position/selection
        var start = this.selectionStart;
        var end = this.selectionEnd;

        var $this = $(this);
        var value = $this.val();

        // set textarea value to: text before caret + tab + text after caret
        $this.val(value.substring(0, start)
                    + "\t"
                    + value.substring(end));

        // put caret at right position again (add one for the tab)
        this.selectionStart = this.selectionEnd = start + 1;

        // prevent the focus lose
        e.preventDefault();
    }
});

The tabs are inserted correctly and are displayed in the textarea as expected. The problem occurs when I then read the value of the textrea and try to replace to tab characters with html formatting.

$("#code-editor").keyup(function (e) {
        var value = $(this).val();
        //Do formatting
        var lines = value.split("\n");

        var newvalue = "";

        for (var i = 0; i < lines.length; i++) {
            lines[i].replace(/\t/g, "<span style='padding-left:3em'></span>");
            lines[i] += "<br />";
            newvalue += lines[i];
        }

        $('#editor-displayarea').html(newvalue);
    });

I have discovered that the tabs do not seem to be preserved when reading from textarea.

Is there a way around this or have I taken the wrong approach?

Thanks.

Update: I have tried using a few variations on the regular expression as stated in the comment below but to no avail.

Answer 1

You are not storing the value when you replace the tabs. Try something like this (I would leave the   in the span as well):

for (var i = 0; i < lines.length; i++) {
    var replaced = lines[i].replace(/\t/g, "<span style='padding-left:3em'>&nbsp;</span>");
    replaced += "<br />";
    newvalue += replaced;
}