javascript利用setInterval进行轮询操作一例

<script  language='javascript'>
var intervalID = null;
//点击‘扫描’按钮
function saveScanInfo(){
var url = "/lhys/scanFile.do";
$.ajax({
url:url,
type:"POST",
success:function(data){
var millisec = 1000*1;
intervalID = setInterval(queryScanFile,millisec);//setInterval()方法第一个参数为js方法名或者js方法，第二个参数为循环的时间间隔
}
});
}

//查询数据库中对应记录是否可以扫描
function queryScanFile(){
var url = "/lhys/queryScanFile.do";
$.ajax({
url:url,
data:{},
type:"POST",
dataType:"text",
beforeSend:function(){
$('#scaningImg').show();
},
success:function(data, textStatus, jqXHR){
//alert(data + "," + textStatus + "," + jqXHR);
//var filePath = "H:/扫瞄管理程序/ScanImages/PC00120140219111832.PDF";
if(data == 'success'){
window.clearInterval(intervalID);
$('#scaningImg').hide();
alert("扫描成功！请点击【上传】按钮上传资料...");
}else if(data == 'failed'){//failed scaning success
alert("扫描文件失败！请重新扫描文件...");
$('#scaningImg').hide();
}else if(data == 'scaning'){
queryScanFile();
}
}
});
}


</script>