Home  >  Article  >  Web Front-end  >  js method to verify uploaded images_javascript skills

js method to verify uploaded images_javascript skills

WBOY
WBOYOriginal
2016-05-16 15:59:341158browse

The example in this article describes the js method of verifying uploaded images. Share it with everyone for your reference. The specific implementation method is as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js验证图片</title>
<script>
 UpLoadFileCheck=function()
 { 
  this.AllowExt=".jpg,.gif";
  //允许上传的文件类型 0为无限制
  //每个扩展名后边要加一个"," 小写字母表示 
  this.AllowImgFileSize=0;
  //允许上传文件的大小 0为无限制 单位:KB 
  this.AllowImgWidth=0;
  //允许上传的图片的宽度 0为无限制 单位:px(像素) 
  this.AllowImgHeight=0;
  //允许上传的图片的高度 0为无限制 单位:px(像素) 
  this.ImgObj=new Image();
  this.ImgFileSize=0;
  this.ImgWidth=0;
  this.ImgHeight=0;
  this.FileExt="";
  this.ErrMsg="";
  this.IsImg=false;//全局变量
 }
 UpLoadFileCheck.prototype.CheckExt=function(obj)
 {
 this.ErrMsg=""; 
 this.ImgObj.src=obj.value; 
 //this.HasChecked=false; 
 if(obj.value=="")
 {
  this.ErrMsg="\n请选择一个文件";  
 }
 else
 {  
  this.FileExt=obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase(); 
  if(this.AllowExt!=0&&this.AllowExt.indexOf(this.FileExt)==-1)
  //判断文件类型是否允许上传 
  { 
  this.ErrMsg="\n该文件类型不允许上传。请上传 "+this.AllowExt+" 类型的文件,当前文件类型为"+this.FileExt;  
  }
 } 
 if(this.ErrMsg!="") 
 {
  this.ShowMsg(this.ErrMsg,false); 
  return false;
 }
 else  
  return this.CheckProperty(obj);  
 }
 UpLoadFileCheck.prototype.CheckProperty=function(obj)
 {
 if(this.ImgObj.readyState!="complete")//
  { 
  sleep(1000);//一秒使用图能完全加载  
  }  
 if(this.IsImg==true)
 {
  this.ImgWidth=this.ImgObj.width;
  //取得图片的宽度 
  this.ImgHeight=this.ImgObj.height;
  //取得图片的高度
  if(this.AllowImgWidth!=0&&this.AllowImgWidth<this.ImgWidth) 
  this.ErrMsg=this.ErrMsg+"\n图片宽度超过限制。请上传宽度小于"+this.AllowImgWidth+"px的文件,当前图片宽度为"+this.ImgWidth+"px"; 
  if(this.AllowImgHeight!=0&&this.AllowImgHeight<this.ImgHeight) 
  this.ErrMsg=this.ErrMsg+"\n图片高度超过限制。请上传高度小于"+this.AllowImgHeight+"px的文件,当前图片高度为"+this.ImgHeight+"px"; 
 }
 this.ImgFileSize=Math.round(this.ImgObj.fileSize/1024*100)/100;
 //取得图片文件的大小 
 if(this.AllowImgFileSize!=0&&this.AllowImgFileSize<this.ImgFileSize) 
  this.ErrMsg=this.ErrMsg+"\n文件大小超过限制。请上传小于"+this.AllowImgFileSize+"KB的文件,当前文件大小为"+this.ImgFileSize+"KB"; 
 if(this.ErrMsg!="") 
 {
  this.ShowMsg(this.ErrMsg,false); 
  return false;
 }
 else 
  return true; 
 } 
 UpLoadFileCheck.prototype.ShowMsg=function(msg,tf)
 //显示提示信息 tf=false 显示错误信息 msg-信息内容 
 { 
 /*msg=msg.replace("\n","<li>"); 
 msg=msg.replace(/\n/gi,"<li>"); 
  */
 alert(msg);
 }
 function sleep(num) 
 { 
  var tempDate=new Date(); 
  var tempStr=""; 
  var theXmlHttp = new ActiveXObject( "Microsoft.XMLHTTP" ); 
  while((new Date()-tempDate)<num ) 
  { 
  tempStr+="\n"+(new Date()-tempDate); 
  try{ 
  theXmlHttp .open( "get", "about:blank&#63;JK="+Math.random(), false ); 
  theXmlHttp .send(); 
  } 
  catch(e){;} 
  } 
  //containerDiv.innerText=tempStr; 
 return; 
 } 
 function c(obj)
 {
 var d=new UpLoadFileCheck(); 
 d.IsImg=true;
 d.AllowImgFileSize=100;
 d.CheckExt(obj)
 }
</script>
</head>
<body>
<input name="" type="file" onchange="c(this)"/>
</body>
</html>

I hope this article will be helpful to everyone’s JavaScript programming design.

Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn