Javascript HTML文档中的滚动位置-如何确定

想象一个HTML文档包含一长串的段落。用户使用滚动条向下滚动文档52%

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如何获取文档的52%或第100段或其他MEDIC？使用以下两个功能，您可以确定您需要什么

// getPageScroll() by quirksmode.com
// use getPageScroll()[0] for horizontal scrolled amount
// use getPageScroll()[1] for vertical scrolled amount
function getPageScroll() {
    var xScroll, yScroll;
    if (self.pageYOffset) {
      yScroll = self.pageYOffset;
      xScroll = self.pageXOffset;
    } else if (document.documentElement && document.documentElement.scrollTop) {
      yScroll = document.documentElement.scrollTop;
      xScroll = document.documentElement.scrollLeft;
    } else if (document.body) {// all other Explorers
      yScroll = document.body.scrollTop;
      xScroll = document.body.scrollLeft;
    }
    return new Array(xScroll,yScroll)
}

// Adapted from getPageSize() by quirksmode.com
function getPageHeight() {
    var windowHeight
    if (self.innerHeight) { // all except Explorer
      windowHeight = self.innerHeight;
    } else if (document.documentElement && document.documentElement.clientHeight) {
      windowHeight = document.documentElement.clientHeight;
    } else if (document.body) { // other Explorers
      windowHeight = document.body.clientHeight;
    }
    return windowHeight
}