如何把用js循环出来的id alert出来看呢

function writeTdone(rowNum,aff)
{
	// rowNum 代表 几点
	// aff 如果==0，代表上午，==1代表下午
	for(i=0; i<7; i++)
	{
		if (aff==0)
		{
			document.write('<td id="0tr'+rowNum+'td'+i+'" class="class_td_activity" onclick="clicks('+i + ',' + rowNum +',this)"><input id="0txt'+rowNum+'txt'+i+'" class="class_text" type="text" readonly="readonly"></td>');
		}
		else
		{
			document.write('<td id="1tr'+rowNum+'td'+i+'" class="class_td_activityone" onclick="clicks('+i + ',' + rowNum +',this)"><input id="1txt'+rowNum+'txt'+i+'" class="class_text" type="text" readonly="readonly"></td>');
		}
	}
} 

function clicks(i,rowNum,tdId)
{
    alert();
｝

function titles(titleNum)
{
	//titleText 意思是把所有的时间放进去
	// titleNum 是所有的时间
	//然后输出出来
	var titleText = new Array("上午12点","上午1点","上午2点","上午3点","上午4点","上午5点","上午6点","上午7点","上午8点","上午9点","上午10点","上午11点","下午12点","下午1点","下午2点","下午3点","下午4点","下午5点","下午6点","下午7点","下午8点","下午9点","下午10点","下午11点");
	document.write('<th rowspan="2" class="class_th_time">'+titleText[titleNum]+'</th>');
}

这里面的id要怎么写才能看的到呢？

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function clicks(i,rowNum,tdId)
{
    alert(tdId.id);
｝