How to autosize a textarea using Prototype?

134

I'm currently working on an internal sales application for the company I work for, and I've got a form that allows the user to change the delivery address.

Now I think it would look much nicer, if the textarea I'm using for the main address details would just take up the area of the text in it, and automatically resize if the text was changed.

Here's a screenshot of it currently.

ISO Address

Any ideas?

@Chris

A good point, but there are reasons I want it to resize. I want the area it takes up to be the area of the information contained in it. As you can see in the screen shot, if I have a fixed textarea, it takes up a fair wack of vertical space.

I can reduce the font, but I need address to be large and readable. Now I can reduce the size of the text area, but then I have problems with people who have an address line that takes 3 or 4 (one takes 5) lines. Needing to have the user use a scrollbar is a major no-no.

I guess I should be a bit more specific. I'm after vertical resizing, and the width doesn't matter as much. The only problem that happens with that, is the ISO number (the large "1") gets pushed under the address when the window width is too small (as you can see on the screenshot).

It's not about having a gimick; it's about having a text field the user can edit that won't take up unnecessary space, but will show all the text in it.

Though if someone comes up with another way to approach the problem I'm open to that too.

I've modified the code a little because it was acting a little odd. I changed it to activate on keyup, because it wouldn't take into consideration the character that was just typed.

resizeIt = function() {
  var str = $('iso_address').value;
  var cols = $('iso_address').cols;
  var linecount = 0;

  $A(str.split("\n")).each(function(l) {
    linecount += 1 + Math.floor(l.le


                    
                    
                        
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One refinement to some of these answers is to let CSS do more of the work.

The basic route seems to be:

Create a container element to hold the textarea and a hidden div
Using Javascript, keep the textarea’s contents synced with the div’s
Let the browser do the work of calculating the height of that div
Because the browser handles rendering / sizing the hidden div, we avoid explicitly setting the textarea’s height.

document.addEventListener('DOMContentLoaded', () => {
    textArea.addEventListener('change', autosize, false)
    textArea.addEventListener('keydown', autosize, false)
    textArea.addEventListener('keyup', autosize, false)
    autosize()
}, false)

function autosize() {
    // Copy textarea contents to div browser will calculate correct height
    // of copy, which will make overall container taller, which will make
    // textarea taller.
    textCopy.innerHTML = textArea.value.replace(/\n/g, '<br/>')
}

html, body, textarea {
    font-family: sans-serif;
    font-size: 14px;
}

.textarea-container {
    position: relative;
}

.textarea-container > div, .textarea-container > textarea {
    word-wrap: break-word; /* make sure the div and the textarea wrap words in the same way */
    box-sizing: border-box;
    padding: 2px;
    width: 100%;
}

.textarea-container > textarea {
    overflow: hidden;
    position: absolute;
    height: 100%;
}

.textarea-container > div {
    padding-bottom: 1.5em; /* A bit more than one additional line of text. */ 
    visibility: hidden;
}

                        
                        
                            answered 2010-01-09T06:57:46.283

@memical had an awesome solution for setting the height of the textarea on pageload with jQuery, but for my application I wanted to be able to increase the height of the textarea as the user added more content. I built off memical's solution with the following:

$(document).ready(function() {
    var $textarea = $("p.body textarea");
    $textarea.css("height", ($textarea.attr("scrollHeight") + 20));
    $textarea.keyup(function(){
        var current_height = $textarea.css("height").replace("px", "")*1;
        if (current_height + 5 <= $textarea.attr("scrollHeight")) {
            $textarea.css("height", ($textarea.attr("scrollHeight") + 20));
        }
    });
});

It's not very smooth but it's also not a client-facing application, so smoothness doesn't really matter. (Had this been client-facing, I probably would have just used an auto-resize jQuery plugin.)

answered 2011-01-04T17:28:40.010

Using ASP.NET, just simply do this:

<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title>Automatic Resize TextBox</title>
        <script type="text/javascript">
            function setHeight(txtarea) {
                txtarea.style.height = txtdesc.scrollHeight + "px";
            }
        </script>
    </head>

    <body>
        <form id="form1" runat="server">
            <asp:TextBox ID="txtarea" runat= "server" TextMode="MultiLine"  onkeyup="setHeight(this);" onkeydown="setHeight(this);" />
        </form>
    </body>
</html>

answered 2013-02-22T19:21:05.573

How to autosize a textarea using Prototype?

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