本代码支持多字符匹配,以空格为分割
function HighLight(nWord) {
        if (nWord != '') {
                var keyword = document.body.createTextRange();
                while (keyword.findText(nWord)) {
                        keyword.pasteHTML("<span style='color:red;'>" + keyword.text + "</span>");
                        keyword.moveStart('character', 1);
                }
        }
}
// 高亮关键字
function highword(nWord) {

        var array = nWord.replace(/(^\s*)|(\s*$)/g, "");
        array = array.split(" ");
        for (var i = 0; i < array.length; i++) {
                HighLight(array[i]);
        }
        document.getElementById("footdiv").style.display = "";
}