i want to know,how is it possible to check automatic all the checkboxes generated in php while page loading.
i mean if the are for example 20records then all to be checked.
I am not sure how this relates exactly to PHP. This sounds like an HTML question. As you are talking about checkboxes, I presume you mean checked as in "there is a tick in the box", rather than the validation "to check something".
If I understand correctly, then the solution is very simple. you just need to add the word checked to the input, like so: