js image processing sample code_javascript skills

Copy code The code is as follows:

var ImgObj=new Image(); //Create a Image object
var AllImgExt=".jpg|.jpeg|.gif|.bmp|.png|"//All image format types
var FileObj,ImgFileSize,ImgWidth,ImgHeight,FileExt,ErrMsg,FileMsg,HasCheked ,IsImg//Global variable image related attributes
//The following are restriction variables
var AllowExt=".jpg|.gif|.doc|.txt|" //File types allowed to be uploaded? Unlimited per A "|" lowercase letter should be added after each extension to indicate
var AllowImgFileSize=70; //The size of the image file allowed to be uploaded. 0 is unlimited unit: KB
var AllowImgWidth=500; //The images allowed to be uploaded The width? is in unlimited units: px (pixels)
var AllowImgHeight=500; //The height of the uploaded image is allowed? is in unlimited units: px (pixels)
HasChecked=false;
function CheckProperty (obj) //Check image attributes
{
FileObj=obj;
if(ErrMsg!="") //Check whether it is the correct image file, return an error message and reset
{
ShowMsg(ErrMsg,false);
return false; //Return
}
ImgFileSize=Math.round(ImgObj.fileSize/1024*100)/100;//Get the size of the image file
ImgWidth=ImgObj.width; //Get the width of the picture
ImgHeight=ImgObj.height; //Get the height of the picture
FileMsg="nPicture size:" ImgWidth "*" ImgHeight "px";
FileMsg=FileMsg "nPicture file size:" ImgFileSize "Kb";
FileMsg=FileMsg "nPicture file extension:" FileExt;
if(AllowImgWidth!=0&&AllowImgWidthErrMsg= ErrMsg "nThe picture width exceeds the limit. Please upload a file with a width smaller than " AllowImgWidth "px. The current image width is " ImgWidth "px";
if(AllowImgHeight!=0&&AllowImgHeightErrMsg=ErrMsg "nThe image height exceeds the limit. Please upload a file with a height less than "AllowImgHeight"px. The current image height is "ImgHeight "px";
if(AllowImgFileSize!=0&&AllowImgFileSizeErrMsg=ErrMsg "nThe image file size exceeds the limit. Please upload files smaller than " AllowImgFileSize "KB, the current file size is " ImgFileSize "KB";
if(ErrMsg!="") ShowMsg(ErrMsg,false);
else ShowMsg(FileMsg,true);
}
ImgObj.onerror=function(){ErrMsg='nThe image format is incorrect or the image is damaged!'}
function ShowMsg(msg,tf) //Display prompt information tf=true Display file information tf=false displays error message msg-information content
{
msg=msg.replace("n","

");
msg=msg.replace(/n/gi,"

");
if(!tf)
{
FileObj.outerHTML=FileObj.outerHTML;
MsgList.innerHTML=msg;
HasChecked=false;
} else{
if(IsImg) PreviewImg.innerHTML="";
else PreviewImg.innerHTML="not Image file";
MsgList.innerHTML=msg;
HasChecked=true;
}
}
function CheckExt(obj)
{
ErrMsg="";
FileMsg="";
FileObj=obj;
IsImg=false;
HasChecked=false;
PreviewImg.innerHTML="Preview area";
if(obj.value==" ")return false;
MsgList.innerHTML="File information processing...";
FileExt=obj.value.substr(obj.value.lastIndexOf(".")).toLowerCase();
if(AllowExt!=0&&AllowExt.indexOf(FileExt "|")==-1) //Determine whether the file type is allowed to be uploaded
{
ErrMsg="nThis file type is not allowed to be uploaded. Please upload a file of " AllowExt " type. The current file type is " FileExt;
ShowMsg(ErrMsg,false);
return false;
}
if(AllImgExt.indexOf(FileExt "|") !=-1) //If it is an image file, perform image information processing
{
IsImg=true;
ImgObj.src=obj.value;
alert(ImgObj.src);
alert(Math.round(ImgObj.fileSize/1024*100)/100);
CheckProperty(obj);
return false;
}else{
FileMsg="nFile extension: " FileExt;
ShowMsg(FileMsg,true);
}
}