Universal Form Validator

Amit Wadhwa Feb 8, 2006

Validate form elements of all kinds: select boxes, text fields (including spaces), radio buttons, force numbers in textfields, etc. Very easy to use. Can be used on all forms.

The JavaScript Source: Forms : Universal Form Validator

Simply click inside the window below, use your cursor to highlight the script, and copy [Control]+C the script into a new file in your text editor (such as Note Pad) and save [Control+S]. The script is yours!!!

/* This script and many more are available free online at
The JavaScript Source :: http://www.javascriptsource.com
Created by: Amit Wadhwa :: http://amitwadhwa.fcpages.com/javascript.com/formvalidator.html */

function checkText(formname, textboxname, displaytext) {
  var localerror = '';
  if(Trim(eval('document.'+formname+'.'+textboxname+'.value'))=='') {
    localerror =  '- '+displaytext+' is Required.\n';
  } else localerror = '';
  return localerror;
}

function checkNum(formname, textboxname, displaytext) {
  var localerror = '';
  if(isNaN(eval('document.'+formname+'.'+textboxname+'.value'))) {
    localerror =  '- '+displaytext+' Should Be A Number With No Spaces.\n';
  } else localerror = '';
  return localerror;
}

function checkSpaces(formname, textboxname, displaytext) {
  var valid = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_'; // define valid characters
  var localerror = '';
  if(!isValid(Trim(eval('document.'+formname+'.'+textboxname+'.value')), valid)) {
    localerror =  '- '+displaytext+' Should Not Contain Spaces.\n';
  } else localerror = '';
  return localerror;
}

function checkSelect(formname, selectboxname, displaytext) {
  var localerror = '';
  if(eval('document.'+formname+'.'+selectboxname+'.selectedIndex')==0) {
    localerror =  '- '+displaytext+' is Required.\n';
  } else localerror = '';
  return localerror;
}

function isValid(string,allowed) {
//  var valid = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; // define valid characters
    for (var i=0; i< string.length; i++) {
      if (allowed.indexOf(string.charAt(i)) == -1) return false;
    }
    return true;
}

function check(formname, submitbutton) {
  var errors = '';
  errors += checkText(formname, 'textfield1', 'Name');
  errors += checkSelect(formname, 'Country', 'Country Of Residence');
  errors += checkText(formname, 'age', 'Age Of Person');
  errors += checkNum(formname, 'age', 'Age Of Person');
  errors += checkRadio(formname, 'Gender', 'Your gender');
  checkThisForm(formname, submitbutton, errors);
}
//-->
</script>

<form name="form1">
  <p>Enter Name: <input type="text" name="textfield1"> (Mandatory)</p>
  <p>Enter Country of Residence:
    <select name="Country">
      <option value="" selected>- Select Country -</option>
      <option value="India">India</option>
      <option value="China">China</option>
      <option value="UK">UK</option>
      <option value="USA">USA</option>
    </select>
    (Mandatory)</p>
  <p>Enter Age: <input type="text" name="age"> (Mandatory, Must be a number)</p>
  <p> Gender
    <input type="radio" name="Gender" value="M"> Male
    <input type="radio" name="Gender" value="F"> Female (Mandatory - select one)</p>
  <p>
    <input type="button" name="Submit" value="submit" onClick="check('form1', this.name);"></p>
</form>
<p><div align="center">
<font face="arial, helvetica" size"-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</div><p>

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