Do not change the security level, before uploading, in the client to determine the size of the picture file

Security | client | upload
Tips collected earlier in the project have recently been used and may be helpful to everyone.





<!--excerpted from 51js-->

<script>
var img=null;
function S ()
{
if (IMG) Img.removenode (TRUE);
Img=document.createelement ("img");
img.style.position= "Absolute";
Img.style.visibility= "hidden";
img.width = 0;
img.height = 0;
Img.attachevent ("onReadyStateChange", ORSC);
Img.attachevent ("onerror", OE);
Document.body.insertAdjacentElement ("BeforeEnd", IMG);
Img.src=inp.value;
}
function OE ()
{
alert ("Cant load img");
}
function ORSC ()
{
if (img.readystate!= "complete") return false;
Alert ("Picture size:" +img.offsetwidth+ "X" +img.offsetheight);
Alert ("Picture size:" +img.filesize);
Btn.disabled=false;
}
</script>
<input id=inp type= "File" >
<br>
<button >test</button><button id=btn disabled>upload</button>

As you can see, it's also very simple, it first defines an IMG object in memory and then uses this object to get the various properties of the IMG object on the client.