PHP keep checkbox checked after submitting form

If the submitted value is not empty, then add the checked="checked" attribute to the checkbox:

<input type="checkbox" name="txtCheck" value="1" <?php if (!empty($_POST['txtCheck'])): ?> checked="checked"<?php endif; ?> />

You can however leave the value attribute intact.

change

<input type="checkbox" name="txtCheck" value="<?php echo $_POST['txtCheck'];?>"  /><br />

to

<input type="checkbox" name="txtCheck" value="your value" <?php if(isset($_POST['txtCheck'])) echo "checked='checked'"; ?>  /><br />

this will keep checkbox checked..