iframe and validate.js

I have iframe inside my page for save data in database.I use validate.js to validate a field inside a iframe.If I validate field outside a iframe means in same page its work.If i do same thing in iframe its doesn't work.I want to know validate.js doesn't work inside a iframe?

I try:

var v = $("#form1").validate({
                     ignore: ':hidden',
                     rules: {
                         txtTitle: { required: true },
                         txtPost: { required: true },
                         txtSummary: { required: true }
                     },
                     messages: {
                         txtTitle: "Please enter a Post Title",
                         txtPost: "Please enter a Post description",
                         txtSummary: "Please enter a Post Summary"
                     }
                 });
 

And in button click I use like this.

 $("#btnPost").live("click", function() {
                     if (v.form()) {
                      alert("Success");
                     }
                     else {
                     alert("fail");
                         return false;
                     }
                 });
 

note:txtTitle,txtPost,txtSummary,btnPost all are iframe controls.Thanks.

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