Question

I am working with a form that has a catcha image. When a user fills out the form, and presses submit ( and only when the captcha number is wrong) the fields are reset or cleared. How can I prevent this from happening?
If a visitor fills out the form, presses submit, the expected behaviour is theform is submitted, or if the captch number is wrong, retain the information that the visitor had input in the fields and ask the visitor to fill in the correct captcha number…

Here is the js:

function MM_validateForm() { //v4.0
if (document.getElementById){
var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=document.getElementById(args[i]);
  if (val) { nm=val.name; if ((val=val.value)!="") {
    if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
      if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
    } else if (test!='R') { num = parseFloat(val);
      if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
      if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
        min=test.substring(8,p); max=test.substring(p+1);
        if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
  } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
} if (errors) alert('The following error(s) occurred:\n'+errors);
document.MM_returnValue = (errors == '');
} }

Answer 1

When you want to prevent the default behaviour you’ve to use a callback function like this:

function onsubmit_handler(evt) {
    if (/* validation is ok */) {
       return true;
    }
    else { /* validation is not ok */
       evt.preventDefault();
       return false;
    }
}

yourfom.onsubmit = onsubmit_handler;