确定HTML元素的内容是否溢出

Question

如果HTML元素溢出其内容,我可以使用JavaScript检查(无论滚动条)吗？例如,一个长小的固定大小的div,溢出属性设置为可见,并且元素上没有滚动条.

Answer 1

通常情况下,你可以比较client[Height|Width]使用scroll[Height|Width],以检测这种...但值是相同的,当溢出是可见的.因此,检测例程必须考虑到这一点:

// Determines if the passed element is overflowing its bounds,
// either vertically or horizontally.
// Will temporarily modify the "overflow" style to detect this
// if necessary.
function checkOverflow(el)
{
   var curOverflow = el.style.overflow;

   if ( !curOverflow || curOverflow === "visible" )
      el.style.overflow = "hidden";

   var isOverflowing = el.clientWidth < el.scrollWidth 
      || el.clientHeight < el.scrollHeight;

   el.style.overflow = curOverflow;

   return isOverflowing;
}

测试在FF3,FF40.0.2,IE6,Chrome 0.2.149.30中.

Answer 2

尝试比较element.scrollHeight/ element.scrollWidth到element.offsetHeight/element.offsetWidth

http://developer.mozilla.org/en/DOM/element.offsetWidth
http://developer.mozilla.org/en/DOM/element.offsetHeight
http://developer.mozilla.org/en/DOM/element. scrollWidth
http://developer.mozilla.org/en/DOM/element.scrollHeight

Answer 3

另一种方法是将元素宽度与其父元素宽度进行比较：

function checkOverflow(elem) {
    const elemWidth = elem.getBoundingClientRect().width
    const parentWidth = elem.parentElement.getBoundingClientRect().width

    return elemWidth > parentWidth
}