顾名思义，通过JS和Ajax来获取上传文件的大小，在上传之前可以有个判断，对上传的文件有所控制，因为js控制文件大小（JS获取文件大小）有些问题，具体大家试下就知道了，在此整理了一下ajax的获取文件大小的方法，比较好用，再调试过程中，出现了c:/fakepath/ 的错误，也将解决方案罗列在下面，以供大家参考
废话少说，代码如下
JS如下：
<script language="Jscript"> function chksize(){ var ticketType = "Oil"; var file1=document.getElementById("txtfile"); var v = file1.value; file1.select(); var realpath = document.selection.createRange().text; var input = "<Record><Type>TicketLoanResult</Type><TicketType>" + realpath + "</TicketType></Record>"; var objXmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); objXmlHttp.Open("POST", "XMLHttpPost.aspx", false); objXmlHttp.Send(input); var returnXml = objXmlHttp.responseText; if(returnXml!=null) { returnXml=parseInt(returnXml/1024/1024); } alert(returnXml); return false; } </script>
后台C#代码：
public partial class XMLHttpPost : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { try { XmlDocument xmlDocumenet = new XmlDocument(); xmlDocumenet.Load(Request.InputStream); string type = xmlDocumenet.SelectSingleNode("descendant::Type").InnerText; string returnMessage = string.Empty; switch (type.Trim()) { case "TicketLoanResult": returnMessage = GetTicketLoanResult(xmlDocumenet); break; default: break; } Response.ContentType = "text/xml"; Response.Write(returnMessage); } catch (Exception exceptional) { //如果有錯誤則返回錯誤信息（Xml格式） string errorMessage = "<Error>" + exceptional.Message + "</Error>"; Response.ContentType = "text/xml"; Response.Write(errorMessage); } finally { Response.End(); } } private string GetTicketLoanResult(XmlDocument input) { XmlNode item = input.SelectSingleNode("descendant::TicketType"); string ticketType = item.InnerText.Trim(); FileStream stream = new FileStream(ticketType,FileMode.Open); return stream.Length.ToString(); } }
完整实例代码点击此处。