javascript 通过滚动移动 DIV

Moving a DIV by scrolling

提问by developerdoug

I'm creating a jQuery scrollbar which scrolls the content in a <div>. It's something like jQuery ScrollPane.

我正在创建一个 jQuery 滚动条，它在 <div> 中滚动内容。它类似于jQuery ScrollPane。

I've come to the point where I need to move the scroll button. My question is: what is the best way to do it without any UI plugin? So when the user clicks on the scroll button it can be moved vertically in its parent container with a mousedown event. How could I do that?

我已经到了需要移动滚动按钮的地步。我的问题是：没有任何 UI 插件的最佳方法是什么？因此，当用户单击滚动按钮时，它可以通过 mousedown 事件在其父容器中垂直移动。我怎么能那样做？

回答by Andy

Here's a starting point, hope that's what you're after:

这是一个起点，希望这就是您所追求的：

$(function() {
    $('.slider').slider();
});

$.fn.slider = function() {
    return this.each(function() {
        var $el = $(this);
        $el.css('top', 0);
        var dragging = false;
        var startY = 0;
        var startT = 0;
        $el.mousedown(function(ev) {
            dragging = true;
            startY = ev.clientY;
            startT = $el.css('top');
        });
        $(window).mousemove(function(ev) {
            if (dragging) {
                // calculate new top
                var newTop = parseInt(startT) + (ev.clientY - startY);
                
                //stay in parent
                var maxTop =  $el.parent().height()-$el.height();          
                newTop = newTop<0?0:newTop>maxTop?maxTop:newTop;
                $el.css('top', newTop );
            }
        }).mouseup(function() {
            dragging = false;
        });
    });
}

.container{
    position:relative;
    border:1px solid red;
    height:100px;
}
.slider{
    height:20px;
    width:20px;
    background:green; 
    position:absolute;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
  <div class="container">
    <div class="slider" />
  </div>
</div>
<br/>
<div class="container">
  <div class="slider" />
</div>

回答by developerdoug

I developed a right nav dock style item with just plain javascript. Here is the link:

我只用普通的 javascript 开发了一个正确的导航码头样式项目。链接在这里：

https://github.com/developerDoug/HtmlJavascriptDockInVS2010

https://github.com/developerDoug/HtmlJavascriptDockInVS2010

Using a ui plugin would be best if you can convince your customer to do so. If not, what you'll need to focus on is hanling mousedown or something similar to that to be noticed that moving has began. The there methods to focus on are: mousedown, mousemove, mouseup.

如果您能说服您的客户这样做，最好使用 ui 插件。如果没有，您需要关注的是处理 mousedown 或类似于要注意移动已经开始的东西。需要关注的方法有：mousedown、mousemove、mouseup。

For example, if on some div, you detect mousedown, you could call a function which basically would be your beginDrag, get x y coordinates, keep a reference to the start coordinates, attachEvent (if IE), addEventListener (for all other browsers).

例如，如果在某个 div 上检测到鼠标按下，则可以调用一个函数，该函数基本上是您的 beginDrag、获取 xy 坐标、保留对开始坐标的引用、attachEvent（如果是 IE）、addEventListener（对于所有其他浏览器）。

ex:

前任：

// keep reference to drag div
_dragObj = new Object();

$("myDragDiv").mousedown(function(e) {
    dragBegin(e);
}

function dragBegin(e) {

    _dragObj = document.getElementById('myDragDiv');

    var x, y;

    if (navigator.userAgent.indexOf("MSIE") >= 0) {
        x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
        y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
    } else {
        x = e.clientX + window.scrollX;
        y = e.clientY + window.scrollY;
    }

    _dragObj.cursorStartX = x;
    _dragObj.cursorStartY = y;

    if (navigator.userAgent.indexOf("MSIE") >= 0) {
        document.attachEvent("onmousemove", dragContinue);
        document.attachEvent("onmouseup", dragEnd);
        window.event.cancelBubble = true;
        window.event.returnValue = false;
    } else {
        document.addEventListener("mousemove", dragContinue, true);
        document.addEventListener("mouseup", dragEnd, true);
        e.preventDefault();
    }
}

function dragContinue(e) {
    var x, y;

    var isIE = _browser.isIE;
    var isWebKitBased = _browser.isWebKitBased;

    if (navigator.userAgent.indexOf("MSIE") >= 0) {
        x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
        y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
    } else {
        x = e.clientX + window.scrollX;
        y = e.clientY + window.scrollY;
    }

    var distance = x - _dragObj.cursorStartX;

    distance = Math.abs(distance);

    // or top, bottom, right
    _dragObj.elNode.style.left = (_dragObj.elStartLeft + x - _dragObj.cursorStartX) + "px";

    if (navigator.userAgent.indexOf("MSIE") >= 0) {
        window.event.cancelBubble = true;
        window.event.returnValue = false;
    } else {
        e.preventDefault();
    }
}

function dragEnd() {
    if (navigator.userAgent.indexOf("MSIE") >= 0) {
        document.detachEvent("onmousemove", dragContinue);
        document.detachEvent("onmouseup", dragEnd);
    } else {
        document.removeEventListener("mousemove", dragContinue, true);
        document.removeEventListener("mouseup", dragEnd, true);
    }
}