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§ Validate form fields are filled in (additional class names)

Makes sure something is entered in form fields.  Uses regex to replace classnames so other classnames aren't affected.

This just makes sure required fields have something in them.  You can do your own validation that the contents meet your criteria.

This also illustrates adding class names to and removing them from elements.

If you don't need the fields to have additional class names, see Simpler validate form fields are filled in (no additional class names).

 



function validateformhighlight(aform) {
  var focusme;
  var classnamei;
  var requiredregex = new RegExp("required");
  var highlightregex = new RegExp("highlightborder");
  for (var i=0;i<aform.length;i++) {
    classnamei = aform.elements[i].className;
    if (requiredregex.test(classnamei) || highlightregex.test(classnamei)) {
      if (aform.elements[i].value=="") {
        if (focusme==undefined)
          focusme=aform.elements[i];
        if (requiredregex.test(classnamei)) {
          aform.elements[i].className = classnamei.replace(/required/,"highlightborder");
        }
      }
      else {
        if(highlightregex.test(classnamei))
          aform.elements[i].className = classnamei.replace(/highlightborder/,"required");
      }
    }
  }
  if (focusme!=undefined) {
    alert("Please fill in the highlighted fields.");
    focusme.focus();
    return false;
  }
  return true;
}
 


Use a form like this (and the css, of course):

 


<html>
  <head>
  <title></title>
<script src='validateformhighlight.js' type='text/javascript'></script>
<style type="text/css">
input, label
{
  float:left;
  display:block;
  width:300px;
}
label
{
  width:120px;
  text-align:right;
  padding:0px 20px 12px 0px;
}
textarea#submissiontext
{
  width:585px; /* 70cols */
  margin:0px 0px 12px 0px;
}
br
{
  clear:left;
}
#formdiv
{
  margin:20px;
}
.highlightborder
{
  border: 2px solid red;
}
</style>
  </head>
  <body>
<form action="process.php" method="post" onSubmit="return validateformhighlight(this)">
<input type="hidden" name="form_tools_form_id" value="1" />
<label for="fname">First Name:</label><input name="fname" id="fname" class="required other"><br>
<label for="lname">Last Name:</label><input name="lname" id="lname" class="required"><br>
<label for="email">Email:</label><input name="email" id="email" class="required other"><br>
<label for="age">Age:</label><input name="age" id="age" maxlength="3" class="required something else"><br>
<label for="city">City:</label><input name="city" id="city" class="required"><br>
<label for="state">State:</label><input name="state" id="state" maxlength="2" class="required"><br>
<label for="submissiontext">Submission:</label>
<textarea name="submissiontext" id="submissiontext" rows="20" cols="70" class="required"></textarea>
<br>
<label>&nbsp;</label><input type="submit" value="Submit" style="width:120px">
</form>
  </body>
</html>

 

 

 

last edited on January 14th, 2010 at 2:21 PM

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The first principle of the military analyst is to figure out how the enemy can hurt you worst with his known capabilities and then plan to stop him, not hope he won’t try it.
Early Honor Harrington series, David Weber