get extension file js from file input code example
Example 1: javascript get file extension
var fileName = "myDocument.pdf";
var fileExtension = fileName.split('.').pop();
Example 2: javascript - get the filename and extension from input type=file
function getFile(filePath) {
return filePath.substr(filePath.lastIndexOf('\\') + 1).split('.')[0];
}
function getoutput() {
outputfile.value = getFile(inputfile.value);
extension.value = inputfile.value.split('.')[1];
}
<input id='inputfile' type='file' name='inputfile' onChange='getoutput()'><br>
Output Filename <input id='outputfile' type='text' name='outputfile'><br>
Extension <input id='extension' type='text' name='extension'>