Prevent file loading

Question

I have <input type="file" onchange="isValidFile(this.value)" />.

function isValidFile(filename)
{
     if (getExtension(filename)!=srt)
     {
          //Don't load the file
     }
}

When you load a file the label of <input type="file" /> change to filename, this show that file is loaded/selected, I want if the file have wrong extension to not load it and leave the label blank. I tried to change the value but read here that its not possible for security reasons.

Answer 1

<form name="abc">
    <input type="file" onchange="isValidFile(this.value)"/>
</form>

<script>
    function isValidFile(filename) {
        if (getExtension(filename) != 'jpg') {
            document.forms['abc'].reset();
            alert("invalid Image");
        }
    }
    function getExtension(filename) {
        return filename.substring(filename.lastIndexOf('.') + 1);
    }
</script>

Try this