select the text by middle button
// ==UserScript==
// @name select text by middle button
// @name:zh-CN 中键选择文本
// @namespace http://tampermonkey.net/
// @version 0.1
// @description select the text by middle button
// @description:zh-CN 用鼠标中键选择文本
// @author Harytfw
// @match http://*/*
// @match https://*/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
var x1=0.0,y1=0.0;
const MIN_MOVEMENT = 10;
const se = document.getSelection();
const LEFT_BUTTON = 0,
MIDDLE_BUTTON = 1;
const STATE_INIT = 0,
STATE_READY = 1,
STATE_WORKING = 2,
STATE_FINISH = 3;
let state = STATE_INIT;
function mousedown(e) {
if(e.button!==MIDDLE_BUTTON){
return;
}
x1=e.clientX;
y1=e.clientY;
const range = document.caretPositionFromPoint(x1, y1);
se.setBaseAndExtent(range.offsetNode,range.offset,range.offsetNode,range.offset);
state = STATE_READY;
}
var x2=0.0,y2=0.0;
function mouseup(e){
if(e.button===MIDDLE_BUTTON){
if(state===STATE_WORKING) state=STATE_FINISH;
else state=STATE_INIT;
}
}
function mousemove(e){
if(state===STATE_INIT)return;
x2=e.clientX;
y2=e.clientY;
if(Math.hypot(x1-x2,y1-y2)>=MIN_MOVEMENT){
if(state===STATE_WORKING || state===STATE_READY){
const range = document.caretPositionFromPoint(x2, y2);
if(se.anchorNode!== null)se.extend(range.offsetNode,range.offset);
state=STATE_WORKING;
}
}
else{
state=STATE_READY;
}
}
function click(e){
if(e.button===MIDDLE_BUTTON && state==STATE_FINISH){
e.preventDefault();
}
state=STATE_INIT;
}
document.addEventListener('mouseup', mouseup);
document.addEventListener('mousedown', mousedown);
document.addEventListener('mousemove', mousemove);
document.addEventListener('click', click);
})();