HTML 对字体的样式的选择

 <script type="text/javascript">        function SetToBold () {            var state = document.queryCommandState ("bold");            switch (state) {            case true:                alert ("The bold formatting will be removed from the selected text.");                break;            case false:                alert ("The selected text will be displayed in bold.");                break;            case null:                alert ("The state of the 'bold' command is indeterminable.");                break;            }            document.execCommand ('bold', true, null);        }    </script>

document 的execCommand 命令非常的强大，基本可以满足android，IOS端对HTML的一系列操作，例如，Bold，Underline，Italic 等等

document queryCommandState 可以查询某操作的状态，是否开启。