var saveFile = new File(et_outpath.text + "/" + (m + 1) + "_" + (n + 1) + houzui);
do {
qlty = qlty-5;
saveFile=new File(exportWeb (saveFile,qlty,format,png8))
saveFile.remove();
exportWeb (saveFile, qlty, format,png8);
if (qlty<=0){
alert("无法压缩至指定文件大小");
app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
ac_doc.selection.deselect();
w.enabled = true;
bt_cut.text = "开始";
return;
}
} while (saveFile.length > parseInt(et_imgkb.text)*1024)
app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);