我制作了一个简单的 JavaScript 拖放类。它可以在拖动时自动向上或向下滚动页面。看到这个jsfiddle。也可以在我的github页面上找到。现在不建议高速拖动。我需要解决这个问题。
下面的代码是库的一部分。
var autoscroll = function (offset, poffset, parentNode) {
var xb = 0;
var yb = 0;
if (poffset.isBody == true) {
var scrollLeft = poffset.scrollLeft;
var scrollTop = poffset.scrollTop;
var scrollbarwidth = (document.documentElement.clientWidth - document.body.offsetWidth); //All
var scrollspeed = (offset.right + xb) - (poffset.right + scrollbarwidth);
if (scrollspeed > 0) {
this.scrollLeft(parentNode, scrollLeft + scrollspeed);
}
scrollspeed = offset.left - (xb);
if (scrollspeed < 0) {
this.scrollLeft(parentNode, scrollLeft + scrollspeed);
}
scrollspeed = (offset.bottom + yb) - (poffset.bottom);
if (scrollspeed > 0) {
this.scrollTop(parentNode, scrollTop + scrollspeed);
}
scrollspeed = offset.top - (yb);
if (scrollspeed < 0) {
this.scrollTop(parentNode, scrollTop + scrollspeed);
}
} else {
var scrollLeft = offset.scrollLeft;
var scrollTop = offset.scrollTop;
var scrollbarwidth = parentNode.offsetWidth - parentNode.clientWidth; //17
var scrollbarheight = parentNode.offsetHeight - parentNode.clientHeight; //17
var scrollspeed = (offset.right + xb) - (poffset.right - scrollbarwidth);
if (scrollspeed > 0) {
this.scrollLeft(parentNode, scrollLeft + scrollspeed);
}
scrollspeed = offset.left - (xb + poffset.left);
if (scrollspeed < 0) {
this.scrollLeft(parentNode, scrollLeft + scrollspeed);
}
scrollspeed = (offset.bottom + scrollbarheight + yb) - (poffset.bottom);
if (scrollspeed > 0) {
this.scrollTop(parentNode, scrollTop + scrollspeed);
}
scrollspeed = offset.top - (yb + poffset.top);
if (scrollspeed < 0) {
this.scrollTop(parentNode, scrollTop + scrollspeed);
}
}
};