Textarea to resize based on content length

user_122994 0
Viewed 299012

I need a textarea where I type my text in the box, it grows in length as needed to avoid having to deal with scroll bars and it need to shrink after delete text! I didn’t want to go down the mootools or jquery route because I have a lightweight form.

javascript
8 Answers

You can check the content's height by setting to 1px and then reading the scrollHeight property:

function textAreaAdjust(element) {
  element.style.height = "1px";
  element.style.height = (25+element.scrollHeight)+"px";
}
<textarea onkeyup="textAreaAdjust(this)" style="overflow:hidden"></textarea>

It works under Firefox 3, IE 7, Safari, Opera and Chrome.

user_1191950

You may also try contenteditable attribute onto a normal p or div. Not really a textarea but it will auto-resize without script.

.divtext {
    border: ridge 2px;
    padding: 5px;
    width: 20em;
    min-height: 5em;
    overflow: auto;
}
<div class="divtext" contentEditable>Hello World</div>

billyswong_477010

Decide a width and check how many characters one line could hold, and then for each key pressed you call a function that looks something like:

function changeHeight()
{
var chars_per_row = 100;
var pixles_per_row = 16;
this.style.height = Math.round((this.value.length / chars_per_row) * pixles_per_row) + 'px';
}

Havn't tested the code.

user_1082080

I don't think there's any way to get width of texts in variable-width fonts, especially in javascript.

The only way I can think is to make a hidden element that has variable width set by css, put text in its innerHTML, and get the width of that element. So you may be able to apply this method to cope with textarea auto-sizing problem.

user_1224230

You can achieve this by using a span and a textarea.

You have to update the span with the text in textarea each time the text is changed. Then set the css width and height of the textarea to the span's clientWidth and clientHeight property.

Eg: 

.textArea {
    border: #a9a9a9 1px solid;
    overflow: hidden;
    width:  expression( document.getElementById("spnHidden").clientWidth );
    height: expression( document.getElementById("spnHidden").clientHeight );
}
user_477380
Related