JavaScript get clipboard data on paste event (Cross browser)

Question

How can a web application detect a paste event and retrieve the data to be pasted?

I would like to remove HTML content before the text is pasted into a rich text edi

Answer 1

Simple version:

document.querySelector('[contenteditable]').addEventListener('paste', (e) => {
    e.preventDefault();
    const text = (e.originalEvent || e).clipboardData.getData('text/plain');
    window.document.execCommand('insertText', false, text);
});

Using clipboardData

Demo : http://jsbin.com/nozifexasu/edit?js,output

Edge, Firefox, Chrome, Safari, Opera tested.

⚠ Document.execCommand() is obsolete now.

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Note: Remember to check input/output at server-side also (like PHP strip-tags)

Answer 2

This solution is replace the html tag, it's simple and cross-browser; check this jsfiddle: http://jsfiddle.net/tomwan/cbp1u2cx/1/, core code:

var $plainText = $("#plainText");
var $linkOnly = $("#linkOnly");
var $html = $("#html");

$plainText.on('paste', function (e) {
    window.setTimeout(function () {
        $plainText.html(removeAllTags(replaceStyleAttr($plainText.html())));
    }, 0);
});

$linkOnly.on('paste', function (e) {
    window.setTimeout(function () {
        $linkOnly.html(removeTagsExcludeA(replaceStyleAttr($linkOnly.html())));
    }, 0);
});

function replaceStyleAttr (str) {
    return str.replace(/(<[\w\W]*?)(style)([\w\W]*?>)/g, function (a, b, c, d) {
        return b + 'style_replace' + d;
    });
}

function removeTagsExcludeA (str) {
    return str.replace(/<\/?((?!a)(\w+))\s*[\w\W]*?>/g, '');
}

function removeAllTags (str) {
    return str.replace(/<\/?(\w+)\s*[\w\W]*?>/g, '');
}

notice: you should do some work about xss filter on the back side because this solution cannot filter strings like '<<>>'