jquery.fn.extend({
alertMessage:function(message){
var txtboxValue = $(this).val();//使用$(this)表示對(duì)哪個(gè)對(duì)象添加了擴(kuò)展方法，這里是指$('#textbox' )
alert(txtboxValue + message);
}
});
$(function(){
$("input[name='btn' ]").click(function(){
$('#textbox' ).alertMessage("是字符串");
})
})

<input type='button' name='btn' value='Alert'/>
<input type='text' id='textbox' value='abc'/>

jQuery.fn.__toggleCheck = function (idPrefix) {
var c = false;
$(this).click(function () {
if (c) c = false;
else c = true;
$("input[type=checkbox][id^=" + idPrefix + "]").each(
function () {
this.checked = c;
}
);
});
};
jQuery.fn.__setRepeaterStyle = function (itemTag, evenStyle, hoverStyle) {
$("#" + this.attr("id") + " " + itemTag + ":odd").addClass(evenStyle);
var cssOriginal = "";
$("#" + this.attr("id") + " " + itemTag + "").mouseover(function () {
cssOriginal = $(this).attr("class");
$(this).addClass(hoverStyle);
});
$("#" + this.attr("id") + " " + itemTag + "").mouseout(function () {
$(this).removeClass();
if (cssOriginal.length > 0) {
$(this).addClass(cssOriginal);
}
});
};

<div id="selBox">
<input type="checkbox" id="a_1" />1
<input type="checkbox" id="a_2" />2
<input type="checkbox" id="a_3" />3
<input type="checkbox" id="a_4" />4
<input type="checkbox" id="a_5" />5
<input type="checkbox" id="a_6" />6
<input type="checkbox" id="a_All" />All</div>
<div id="a_All1">Check</div>
</div>
<style type="text/css">
table tr {}
table .rowStyle { background:#dedede;}
table .hoverStyle {font-weight:bold; color:Red; background-color:Gray;}
</style>
<table id="tb" style="width:100%; border:solid 1px #dedede;">
<tr>
<td>1</td>
</tr>
<tr>
<td>1</td>
</tr>
<tr>
<td>1</td>
</tr>
</table>
<script type="text/javascript">
$("#a_All").__toggleCheck("a_");
$("#a_All1").__toggleCheck("a_");
$("#tb").__setRepeaterStyle("tr", "rowStyle", "hoverStyle");
</script>