js method to verify uploaded images_javascript skills
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?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.
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