onsubmit is still submitting the form even if it returns false?

I have a form in HTML page. It includes:

<form action="result.html" method="get" onsubmit="return ValidationEvent()">

So even the ValidationEvent() returns false I can render the result.html. Below is the definition of the function:

// Below Function Executes On Form Submit

function validation() {

// Storing Field Values In Variables
var name = document.getElementById("name").value;
var email = document.getElementById("email").value;
var contact = document.getElementById("contact").value;
// Regular Expression For Email
var emailReg = /^([w-.]+@([w-]+.)+[w-]{2,4})?$/;

// Conditions
if (name != '' && email != '' && contact != '') {
    if (emailReg.test(email)==true) {
        //  if (email.match(emailReg)) 
        if (document.getElementById("male").checked || document.getElementById("female").checked) {
            if (contact.length == 10) {
                alert("All type of validation has done on OnSubmit event.");
                console.log("All type of validation has done on OnSubmit event.")
                return true;
            } 
            else {
                alert("The Contact No. must be at least 10 digit long!");
                console.log("The Contact No. must be at least 10 digit long!");
                return false;
            }
        } 
        else {
            alert("You must select gender.....!");
            return false;
        }
    } 
    else {
        alert("Invalid Email Address...!!!");
        return false;
    }
} 
else {
    alert("All fields are required.....!");
    return false;
}

}

How can prevent the form to be submitted.