防止在用户输入错误时重新加载页面

Question

i creating a registration page like this

<form name='registration' action="registration.php" method="post" onSubmit="return formValidation();">
    FirstName:<input type = "Text" name = "firstname">
    <input type = "submit" name = "register" value="register">
</form>

and here is my javascript function

function formValidation() {  
   var fn = document.registration.firstname;
   if ( fname_validation( fn ) ) {}
}

function fname_validation( fn ) {
   var fn_len = fn.value.length;
   var fn_char = /^[A-Za-z]+$/;
   if ( fn_len == 0 ) {
       alert("first name cannot empty");
       return false;
   }
   if ( !fn.value.match( fn_char ) ) {
       alert("first name must enter alphabet only");
       return false;
   } else {
       return true;
   }
}

the registration form is working but in case user input a number, it will alert and reload the page which will refresh the page. if i want when user wrong input and not refreshing the page to keep the user input, how to do it?

Answer 1

In your javascript you should return the proper value...

Example:

function formValidation() {  
   var fn = document.registration.firstname;
   return fname_validation( fn );
}

Answer 2

Add return false in form submit

<form name='registration' action="registration.php" method="post" onSubmit="return formValidation();return false;">
    FirstName:<input type = "Text" name = "firstname">
    <input type = "submit" name = "register" value="register">
    </form>

Answer 3

为了防止表单提交，只需在formValidation（）函数中返回false