Shorten string without cutting words in JavaScript

If I understand correctly, you want to shorten a string to a certain length (e.g. shorten "The quick brown fox jumps over the lazy dog" to, say, 6 characters without cutting off any word).

If this is the case, you can try something like the following:

var yourString = "The quick brown fox jumps over the lazy dog"; //replace with your string.
var maxLength = 6 // maximum number of characters to extract

//trim the string to the maximum length
var trimmedString = yourString.substr(0, maxLength);

//re-trim if we are in the middle of a word
trimmedString = trimmedString.substr(0, Math.min(trimmedString.length, trimmedString.lastIndexOf(" ")))

There are lots of ways to do it, but a regular expression is a useful one line method:

"this is a longish string of text".replace(/^(.{11}[^\s]*).*/, "$1"); 
//"this is a longish"

This expressions returns the first 11 (any) characters plus any subsequent non-space characters.

Example script:

<pre>
<script>
var t = "this is a longish string of text";

document.write("1:   " + t.replace(/^(.{1}[^\s]*).*/, "$1") + "\n");
document.write("2:   " + t.replace(/^(.{2}[^\s]*).*/, "$1") + "\n");
document.write("5:   " + t.replace(/^(.{5}[^\s]*).*/, "$1") + "\n");
document.write("11:  " + t.replace(/^(.{11}[^\s]*).*/, "$1") + "\n");
document.write("20:  " + t.replace(/^(.{20}[^\s]*).*/, "$1") + "\n");
document.write("100: " + t.replace(/^(.{100}[^\s]*).*/, "$1") + "\n");
</script>

Output:

1:   this
2:   this
5:   this is
11:  this is a longish
20:  this is a longish string
100: this is a longish string of text