jQuery / JS，删除/修剪尾随html换行符？

Question

I'm looking for some ideas for the most efficient way to remove trailing html < br /> tags using javascript or jquery.

RULES:

1. The br, at the front and end must be removed.
2. It must remove non-closing and self-closing br tags.
3. All br within the textual content must remain untouched.

---

THE HTML:

<div class="generatedContent">
    <br>My awesome content.
    <br><br>Some More awesome content.
    <br>
    <br>
    <br>I still need the content written here<br/>
    <br>
    <br>
    <br>
    <br>
    <br>
    <br>
</div>

---

THE DESIRED OUTPUT:

<div class="generatedContent">
    My awesome content.
    <br><br>Some More awesome content.
    <br>
    <br>
    <br>I still need the content written here
</div>

Answer 1

Can't understand why you'd want to to use regular expressions for this, as most answers are. Using DOM methods is easy here:

function isBrOrWhitespace(node) {
    return node && ( (node.nodeType == 1 && node.nodeName.toLowerCase() == "br") ||
           (node.nodeType == 3 && /^\s*$/.test(node.nodeValue) ) );
}

function trimBrs(node) {
    while ( isBrOrWhitespace(node.firstChild) ) {
        node.removeChild(node.firstChild);
    }
    while ( isBrOrWhitespace(node.lastChild) ) {
        node.removeChild(node.lastChild);
    }
}

$(".generatedContent").each( function() {
    trimBrs(this);
} );

Answer 2

Try this:

var everything = $('.generatedContent').contents();
for(var i=everything.length-1;i>0;i--)
{
    if((everything.get(i).tagName == 'BR'
           && everything.get(i-1).tagName == 'BR')
        || (everything.get(i).textContent.match(/\w/)==null))
        $(everything.get(i)).remove();
    else
        break;
}

It seems to work in FF and IE7, that I've tried.

Answer 3

Could probably be improved but it should work:

$('.generatedContent').each(function() {
    var str = $(this).html();
    var regex1 = /^([\n ]*)(<br.*?>)*/;
    var regex2 = /(<br.*?>)*([\n ]*)$/;
    str = str.replace(regex1,'');
    str = str.replace(regex2,'');
    $(this).html(str);
})

Answer 4

Pretty simple. Take the HTML of the generatedContent div then apply the following regex:

s = s.replace(/^(\s*<br\s*\/?>)*\s*|\s*(<br\s*\/?>\s*)*$/g, '')

There's probably a more efficient way to do it using pure JS, but this is probably more succint.

Answer 5

Here is a non regex solution that works for me in Firefox. Could probably use some better edge case handling but the idea works. Basically it just finds the first and last non-empty text nodes and removes all nodes before and after.

var firstValidTextNode = -1;
var lastValidTextNode = -1;
$('.generatedContent').contents().each(function(index){
    if (this.nodeType != 1 && $.trim($(this).text()).length) {
        if (firstValidTextNode == -1) firstValidTextNode = index;
        lastValidTextNode = index;
    }
});

if (lastValidTextNode != -1 && firstValidTextNode != -1)
    $('.generatedContent').contents().slice(0, firstValidTextNode).remove().end().slice(lastValidTextNode + 1).remove();