jQuery convert line breaks to br (nl2br equivalent)

jQuery convert line breaks to br (nl2br equivalent)

I’m having jQuery take some textarea content and insert it into an li.
I want it to visually retain the line breaks.
There must be a really simple way to do this…

Solutions/Answers:

Solution 1:

demo: http://so.devilmaycode.it/jquery-convert-line-breaks-to-br-nl2br-equivalent

function nl2br (str, is_xhtml) {   
    var breakTag = (is_xhtml || typeof is_xhtml === 'undefined') ? '<br />' : '<br>';    
    return (str + '').replace(/([^>\r\n]?)(\r\n|\n\r|\r|\n)/g, '$1'+ breakTag +'$2');
}

Solution 2:

you can simply do:

textAreaContent=textAreaContent.replace(/\n/g,"<br>");

Solution 3:

Put this in your code (preferably in a general js functions library):

String.prototype.nl2br = function()
{
    return this.replace(/\n/g, "<br />");
}

Usage:

var myString = "test\ntest2";

myString.nl2br();

creating a string prototype function allows you to use this on any string.

Solution 4:

In the spirit of changing the rendering instead of changing the content, the following CSS makes each newline behave like a <br>:

white-space: pre;
white-space: pre-line;

Why two rules: pre-line only affects newlines (thanks for the clue, @KevinPauli). IE6-7 and other old browsers fall back to the more extreme pre which also includes nowrap and renders multiple spaces. Details on these and other settings (pre-wrap) at mozilla and css-tricks (thanks @Sablefoste).

While I’m generally averse to the S.O. predilection for second-guessing the question rather than answering it, in this case replacing newlines with <br> markup may increase vulnerability to injection attack with unwashed user input. You’re crossing a bright red line whenever you find yourself changing .text() calls to .html() which the literal question implies would have to be done. (Thanks @AlexS for highlighting this point.) Even if you rule out a security risk at the time, future changes could unwittingly introduce it. Instead, this CSS allows you to get hard line breaks without markup using the safer .text().

Solution 5:

Solution

Use this code

jQuery.nl2br = function(varTest){
  return varTest.replace(/(\r\n|\n\r|\r|\n)/g, "<br>");
};

Solution 6:

to improve @Luca Filosofi’s accepted answer,

if needed, changing the beginning clause of this regex to be /([^>[\s]?\r\n]?) will also ingore the cases where the newline comes after a tag AND some whitespace, instead of just a tag immediately followed by a newline