转JS--通过按钮直接把input或者textarea里的值复制到粘贴板里

document.activeElement属性为HTML 5中新增的document对象的一个属性，该属性用于返回光标所在元素。当光标未落在页面中任何元素内时，属性值返回body元素。

setSelectionRange(start, end) 设置选中文本起始位置与结束位置

execCommand方法是执行一个对当前文档，当前选择或者给出范围的命令

    点击按钮复制textarea文本框中内容

<script type="text/javascript">
	function copyTextAreaCt()
		{
			var oContent=document.getElementById("content");
			oContent.select(); // 选择对象
			document.execCommand("Copy"); // 执行浏览器复制命令
			alert("复制完毕，可粘贴");
		}
	</script>
<textarea cols="20" rows="10" id="content" value="">This is a paragraph......</textarea>
<input type="button" onClick="copyTextAreaCt()" value="点击复制代码" />

    转 通过按钮直接把input或者textarea里的值复制到粘贴板里

function copyToClipboard(elem) {
    // create hidden text element, if it doesn't already exist
    var targetId = "_hiddenCopyText_";
    var isInput = elem.tagName === "INPUT" || elem.tagName === "TEXTAREA";
    var origSelectionStart, origSelectionEnd;
    if (isInput) {
        // can just use the original source element for the selection and copy
        target = elem;
        origSelectionStart = elem.selectionStart; //selectionStart光标的开始位置
        origSelectionEnd = elem.selectionEnd; //selectionEnd 光标的结束位置
    } else {
        // must use a temporary form element for the selection and copy
        target = document.getElementById(targetId);
        if (!target) {
            var target = document.createElement("textarea");
            target.style.position = "absolute";
            target.style.left = "-9999px";
            target.style.top = "0";
            target.id = targetId;
            document.body.appendChild(target);
        }
        target.textContent = elem.textContent;
    }
    // select the content
    var currentFocus = document.activeElement;//获取当前页面活动的元素
    target.focus();
    target.setSelectionRange(0, target.value.length);
 
    // copy the selection
    var succeed;
    try {
        succeed = document.execCommand("copy");
    } catch(e) {
        succeed = false;
    }
    // restore original focus
    if (currentFocus && typeof currentFocus.focus === "function") {
        currentFocus.focus();
    }
 
    if (isInput) {
        // restore prior selection 恢复之前的选择
        elem.setSelectionRange(origSelectionStart, origSelectionEnd);
    } else {
        // clear temporary content
        target.textContent = "";
    }
    return succeed;
}
 
//直接调用这个方法：
copyToClipboard(document.getElementById("name"));

文章转自  http://blog.csdn.net/qq377751971/article/details/65446247

              http://www.cnblogs.com/tylerdonet/p/4533782.html

              http://showlike.iteye.com/blog/1073642