javascript jQuery / JS 获取 textarea 的滚动条高度
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jQuery / JS get the scrollbar height of an textarea
提问by iWeb
I've got a textarea with a fixed height. When the user types text into the textarea a scrollbar will show up after the user typed some text in it.
我有一个固定高度的文本区域。当用户在 textarea 中键入文本时，会在用户在其中键入一些文本后显示滚动条。
How can I get the scrollbar height using jQuery or plain JavaScript? I've been searching for this for hours, but couldn't find anything. I can't just insert a div and get the scrollbar height via the div offset because a textarea is not allowed to have child elements.
如何使用 jQuery 或纯 JavaScript 获取滚动条高度？我一直在寻找这个数小时，但找不到任何东西。我不能只插入一个 div 并通过 div 偏移量获取滚动条高度，因为 textarea 不允许有子元素。
Please don't give me a link to a jQuery Plug-In that does the job. I want to learn something.
请不要给我一个链接到一个 jQuery 插件来完成这项工作。我想学点东西。
回答by kennebec
textarea.scrollHeight
returns an integer (pixels)
返回一个整数（像素）
回答by Kashyap Makadia
$.each($("textarea"), function () {
var scrollHeight = parseInt(this.scrollHeight);
if ($("this").val() != "" && isNaN(scrollHeight) == false && scrollHeight > 0 && scrollHeight > $(this).height()) {
console.log($(this).attr("id"));
$(this).height(scrollHeight);
}
});
回答by Akash gupta
Please note that you should exclude the upper paddingand the lower paddingof the textarea while comparing the scrollHeight.
请注意，在比较 scrollHeight 时，您应该排除textarea的上边距和下边距。
Example
例子
var scrollHeight = $("#textarea_id")[0].scrollHeight;
var padding = 14; //upperpadding 7 and lower padding 7.
if($("#textarea_id")[0].height() < (scrollHeight - padding)) {
$("#textarea_id")[0].height(scrollHeight - padding);
}
