js tags

HTML

<input type="text" id="tag" />
<input type="button" id="pasteTag" value="add tag" />

JavaScript

$("#pasteTag").click(function () {
    var tag = $("#tag").val();
    var tagLength = $("#tagBox span").length;
    var tagText = $("#tagBox span").text();

    if (tag == "") {
        alert("请输入标签名称");
    } else {
        var div = "<div id='tagBox' class='tagBox'><span>" + tag + "<input type='hidden' value='" + tag + "'name='tag' /></span></div>";

        if ($("#tagBox").length < 1) {
            $(this).parent().append(div);
        } else {
            if (tagLength < 3) {

                if ($("#tagBox span:contains('" + tag + "')").length == 0) {
                    $("#tagBox").append("<span>" + tag + "<input type='hidden' value='" + tag + "'name='tag' /></span>");
                } else {
                    alert("不能相同")
                }
            } else {
                alert("最多添加3个标签");
            }
        }
    }
    // $('#tag').val('');
    return false;
})