<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" />

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"));