How do I use javascript to prevent form submission because of empty fields?

Question

How do I make a script in javascript to output an error and prevent form submission with empty fields in the form? Say the form name is \"form\" and the input name is \"name\".

Answer 1

HTML Code :-

Javascript Code :-

  function runMyFunction()
    {
        if (document.getElementsByName("name")[0].value == "")
        {
            alert("Please enter value");
        }
        else
        {
            var form= document.getElementsByName("form")[0];
            form.submit();        
        }
    }