选择移动到Div之外时停止滚动

Question

I have a div that I want to be scrollable via mousewheel/scrollbars and by clicking and dragging, so I added a mouse listener to handle it:

container
  .mousedown(function() {
  container.css({
    'cursor': 'move',
    "user-select": "none" //disable selecting text
  });
  container.on('mousemove', function(e) {
    if(lastE) {
      container.scrollLeft(container.scrollLeft() - (e.pageX-lastE.pageX));
      container.scrollTop(container.scrollTop() - (e.pageY-lastE.pageY));
    }
    lastE=e;
  })
})
  .mouseup(function() {
  container.off('mousemove');
  container.css({
    'cursor': 'auto',
    "user-select": "default"
  });
  lastE=undefined;
});

However, when you're dragging and you mouse out of the div, the browser acts like you're selecting text and 'helpfully' starts scrolling the other way to allow you to select more, even though I have text selection disabled, and I can't find a way to make it stop.

https://jsfiddle.net/vej2fkdf/

Answer 1

You can try setting the overflow to hidden. It removes the scrollbars, but it DOES prevent the issue you're seeing. You can even do this only when the mouse enters/leaves

var lastE; //last event, used for comparing mouse position
var container = $('#container');
var out = false;

container
  .mousedown(function() {
  container.css({
    'cursor': 'move',
    "user-select": "none" //disable selecting text
  });
  container.on('mousemove', function(e) {
    if(lastE) {
      container.scrollLeft(container.scrollLeft() - (e.pageX-lastE.pageX));
      container.scrollTop(container.scrollTop() - (e.pageY-lastE.pageY));
    }
    lastE=e;
  });
  container.mouseleave(function () {
    container.css({
      'cursor': 'move',
      'overflow':'hidden',
      "user-select": "none" //disable selecting text
    });
  });
  container.mouseenter(function () {
    container.css({
      'cursor': 'move',
      'overflow':'scroll',
      "user-select": "none" //disable selecting text
    });
  });
})

$(document).mouseup(function() {
  container.off('mousemove');
  container.off('mouseleave');
  container.off('mouseenter');
  container.css({
    'cursor': 'auto',
    "user-select": "default",
    "overflow": "scroll"
  });
  lastE=undefined;
});

https://jsfiddle.net/vej2fkdf/4/

Answer 2

Based on caspian's answer, I modified it so that instead of removing the scrollbars (which looks bad), it records the current scroll position and then repeatedly resets the scroll position until the mouse reenters the div or the mouse is released:

var mouseLeftX;
var mouseLeftY;

container
  .mousedown(function() {
    container.css({
      'cursor': 'move',
      "user-select": "none" //disable selecting text
    });
    container.on('mousemove', function(e) {
      if(lastE) {
        container.scrollLeft(container.scrollLeft() - (e.pageX-lastE.pageX));
        container.scrollTop(container.scrollTop() - (e.pageY-lastE.pageY));
      }
      lastE=e;
    });
    container.mouseleave(function () {
      mouseLeftX = container.scrollLeft();
      mouseLeftY = container.scrollTop();
      container.scroll(function() {
       if(lastE) {
          container.scrollLeft(mouseLeftX);
          container.scrollTop(mouseLeftY);
        }
      })
    });
    container.mouseenter(function () {
        container.off('scroll');
      container.css({
        'cursor': 'move',
        "user-select": "none" //disable selecting text
      });
    });
  })

$(document).mouseup(function() {
  container.off('mousemove');
  container.off('mouseleave');
  container.off('mouseenter');
  container.off('scroll');
  container.css({
    'cursor': 'auto',
    "user-select": "default",
  });
  lastE=undefined;
});

https://jsfiddle.net/vej2fkdf/5/

Still not perfect, as there is a time as the user is mousing over the scrollbars where the browser drag-to-select is going but before mouseleave fires (it doesn't fire until you leave the scrollbar), so there is a bit of scrolling, but it's not as bad...

Answer 3

In the fiddle, I didn't have issues with the text problems, but perhaps, depending on your browser, you'll need to update the user select also with those compatible with other browsers?

-webkit-user-select: none;  /* Chrome all / Safari all */
-moz-user-select: none;     /* Firefox all */
-ms-user-select: none;      /* IE 10+ */
user-select: none;