Greasy Fork

Disable drag and drop for selected text

I hate when I accidentily would drag selected a text while struggling to select a proper fragment of text. I found a script that blocks dragging links when I would like to select text from it horizontally, but still allow to drag it when I do it vertically.

"use strict";

    function caretPositionFromPoint(x, y) {
        if (document.caretPositionFromPoint) {
            return document.caretPositionFromPoint(x, y);
        }
        var r = document.caretRangeFromPoint(x, y);
        return {
            offsetNode: r.startContainer,
            offset: r.startOffset
        };
    }

    function inSelect(caretPos, selection){
        var i, len = selection.rangeCount, range;
        for (i = 0; i < len; i++) {
            range = selection.getRangeAt(i);
            if (range.isPointInRange(caretPos.offsetNode, caretPos.offset)) {
                return true;
            }
        }
        return false;
    }

    var force = {
        target: null,
        select: getSelection(),
        currentPos: {
            x: null,
            y: null
        },
        startPos: {
            x: null,
            y: null
        },
        lastMouseDownPos: {
            x: null,
            y: null
        },
        handleEvent: function(e){
            var caretPos, a, movementX, movementY, select;

            if (e.type == "click") {

                if (e.ctrlKey || e.shiftKey || e.altKey || e.button) {
                    return;
                }

                // Fix browser clicking issue.
                select = window.getSelection();
                if (this.uninitFlag || !select.isCollapsed && e.pageX && e.pageY && (e.pageX != this.lastMouseDownPos.x || e.pageY != this.lastMouseDownPos.y)) {
                    e.preventDefault();
                    e.stopImmediatePropagation();
                }

            } else if (e.type == "mousedown") {

                if (e.ctrlKey || e.shiftKey || e.altKey || e.button) {
                    return;
                }

                // Trak clicking to solve this:
                // https://greasyfork.org/ru/forum/discussion/1898/doesn-t-work-on-some-sites
                this.lastMouseDownPos.x = e.pageX;
                this.lastMouseDownPos.y = e.pageY;

                this.uninitFlag = false;

                if (e.target.nodeName == "IMG") {
                    this.imgFlag = true;
                }

                select = window.getSelection();
                if (!select.isCollapsed) {
                    caretPos = caretPositionFromPoint(e.pageX - window.scrollX, e.pageY - window.scrollY);
                    if (!inSelect(caretPos, select)) {
                        select.collapse(caretPos.offsetNode, caretPos.offset);
                    }
                }

            } else if (e.type == "mouseup") {

                this.checkMove = false;
                this.imgFlag = false;

                if (!this.target) {
                    return;
                }

                this.uninitFlag = true;
                this.uninit();

            } else if (e.type == "mousemove") {

                this.moveX = e.pageX - this.currentPos.x;
                this.moveY = e.pageY - this.currentPos.y;
                this.currentPos.x = e.pageX;
                this.currentPos.y = e.pageY;

                if (!this.target) {
                    return;
                }

                select = window.getSelection();
                caretPos = caretPositionFromPoint(this.currentPos.x - window.scrollX, this.currentPos.y - window.scrollY);
                if (!this.multiSelect) {
                    select.extend(caretPos.offsetNode, caretPos.offset);
                } else {
                    this.range.setEnd(caretPos.offsetNode, caretPos.offset);
                }

            } else if (e.type == "dragstart") {

                if (e.button || e.altKey || e.shiftKey) {
                    return;
                }

                if (this.imgFlag) {
                    this.imgFlag = false;
                    return;
                }

                a = e.target;
                while (a.nodeName != "A" && a.nodeName != "HTML") {
                    a = a.parentNode;
                }

                if (!a.href) {
                    return;
                }

                movementX = e.pageX - this.currentPos.x;
                movementY = e.pageY - this.currentPos.y;

                if (!movementX && !movementY) {
                    movementX = this.moveX;
                    movementY = this.moveY;
                }
                if (Math.abs(movementX) < Math.abs(movementY)) {
                    return;
                }

                e.preventDefault();
                this.target = a;
                this.init(e);
            }
        },
        init: function(e){
            var select = window.getSelection();

            this.startPos.x = e.pageX;
            this.startPos.y = e.pageY;

            this.multiSelect = e.ctrlKey;

            var caretPos = caretPositionFromPoint(this.startPos.x - window.scrollX, this.startPos.y - window.scrollY);
            if (!this.multiSelect) {
                select.collapse(caretPos.offsetNode, caretPos.offset);
            } else {
                this.range = new Range();
                this.range.setEnd(caretPos.offsetNode, caretPos.offset);
                this.range.collapse();
                select.addRange(this.range);
            }

            this.target.classList.add("force-select");

        },
        uninit: function(){

            this.target.classList.remove("force-select");
            this.target = null;
            this.range = null;
            this.multiSelect = false;

        }
    };

    document.addEventListener("mousemove", force, false);
    document.addEventListener("mouseup", force, false);
    document.addEventListener("mousedown", force, true);
    document.addEventListener("click", force, true);
    document.addEventListener("dragstart", force, true);
    document.addEventListener("DOMContentLoaded", function(){
        GM_addStyle(".force-select{ -moz-user-select: text!important; }");
    }, false);

I would like someone to modify that script to work on selected text the same way (or on both selected text and links to have one unified script). I use Waterfox.