Bootstrap ソース コード分析ツールチップ、ポップオーバー

$element   = $element || <span style="color: #0000ff">this</span>.$element <span style="color: #008000">//</span><span style="color: #008000">如果没有传入参数，则以$element（触发tooltip事件的元素）为准</span>

    <span style="color: #0000ff">var</span> el     = $element[0<span style="color: #000000">]
    </span><span style="color: #0000ff">var</span> isBody = el.tagName == 'BODY'

    <span style="color: #0000ff">var</span> elRect    =<span style="color: #000000"> el.getBoundingClientRect()
    </span><span style="color: #0000ff">if</span> (elRect.width == <span style="color: #0000ff">null</span><span style="color: #000000">) {
      </span><span style="color: #008000">//</span><span style="color: #008000"> width and height are missing in IE8, so compute them manually; see https://github.com/twbs/bootstrap/issues/14093</span>
      elRect = $.extend({}, elRect, { width: elRect.right - elRect.left, height: elRect.bottom -<span style="color: #000000"> elRect.top })
    }
    </span><span style="color: #0000ff">var</span> elOffset  = isBody ? { top: 0, left: 0<span style="color: #000000"> } : $element.offset()
    </span><span style="color: #0000ff">var</span> scroll    = { scroll: isBody ? document.documentElement.scrollTop ||<span style="color: #000000"> document.body.scrollTop : $element.scrollTop() }
    </span><span style="color: #0000ff">var</span> outerDims = isBody ? { width: $(window).width(), height: $(window).height() } : <span style="color: #0000ff">null</span>

<span style="color: #0000ff">return</span> $.extend({}, elRect, scroll, outerDims, elOffset)