iam using a form in my vue js app.And the form is from my main website, so that i am including the same form using

"vue-friendly-iframe": "^0.20.0",

for that i added

<vue-friendly-iframe src="url" @load="afterLoad()" id="formFrame"></vue-friendly-iframe>

and the url replaces my original form url.The form is loading perfectly.

so next i want to add my logged in user id to the form's hidden user if textfield after page load. so i added

@load="afterLoad()"

and

afterLoad(){
            console.log("setting user token");
            var formFrame=document.getElementById("formFrame");
            if(formFrame)
                formFrame.document.getElementById("accessories-form").user_id.value = this.$token;
        }

But i couldnt set the user id.How can i do that.Thanks in advance

And my vue js app is hosted in subdomain whereas actual forms are hosted in the primary domain