[SOLVED] How to pass nothing to a function

[garethhall]

Hello Guys,

 

Can some please me and tel how can I pass a null or no value to a function. I have the 2 scripts below and I am writing my JS this way so I can recall it and use it on multiple pages. But as I am sure you can see I don't have a form element called lastName and Fax thus my JS return an undefined error. So When I call me function how do I tell it that that element does not exists?

 

I always thought I can just leave in blank or pass it nothing like this " " but I am wrong?

 

 

HTML Page

<form name="frmContact" method="post">
                	<table cellpadding="0" cellspacing="0" border="0" width="100%">
                    	<tr>
                       	  <td align="right" width="15%" class="label">Name:</td>
                            <td width="85%" ><input type="text" name="name" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_name"></span></td>
                        </tr>
                    	<tr>
                        	<td align="right" class="label">Phone:</td>
                            <td ><input type="text" name="phone" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_phone"></span></td>
                        </tr>
                    	<tr>
                        	<td align="right"  class="label">Email:</td>
                            <td ><input type="text" name="email" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_email"></span></td>
                        </tr>
                    	<tr>
                        	<td align="right" valign="top" class="label">Message:</td>
                            <td ><textarea name="message" cols="20" rows="5" class="textarea"></textarea></td>
                          <td > </td>
                            <td></td>
                        </tr>
                    	<tr>
                        	<td align="right" valign="top" class="label"> </td>
                            <td ><input type="button" name="submit" id="submit" value="Submit" onclick="validate('frmContact', 'name', '', 'email', 'phone', '', 'CMS/cmsImages/approvedMark.gif', 'CMS/cmsImages/rejectMark.png');"/></td>
                          <td > </td>
                        </tr>
                    </table>
    </form> 

 

 

Javascript

// Validation Filters
var emailReg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
var nameReg = /[A-Za-z\'\-]/;
var phoneReg = /[0-9\(\)\-\+ ]{7,16}/;

function validate(frmName, fieldName, fieldLastName, fieldEmail, fieldPhone, fieldFax, apprvMK, rejectMK){
// Set Variables to hold values and followed by Element Name
var name  = document.forms[frmName].elements[fieldName].value;
var nameElementName  = document.forms[frmName].elements[fieldName].name;
var lastName  = document.forms[frmName].elements[fieldLastName].value;
var lastNameElementName  = document.forms[frmName].elements[fieldLastName].name;
var emailAddress  = document.forms[frmName].elements[fieldEmail].value;
var emailElementName  = document.forms[frmName].elements[fieldEmail].name
var phone  = document.forms[frmName].elements[fieldPhone].value;
var phoneElementName  = document.forms[frmName].elements[fieldPhone].name;
var fax  = document.forms[frmName].elements[fieldFax].value;
var faxElementName  = document.forms[frmName].elements[fieldFax].name;

// This runs the validation and updates the Page
function runValidation(myField, MyReg, MyElementName){
	if(!myField.match(MyReg)){
		document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+rejectMK+"' width='12' height='12' />";
	}else{
		document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+apprvMK+"' width='12' height='12' />";
	}
}

runValidation(name, nameReg, nameElementName);
runValidation(lastName, nameReg, lastNameElementName);
runValidation(emailAddress, emailReg, emailElementName);
runValidation(phone, phoneReg, phoneElementName);
runValidation(fax, phoneReg, faxElementName);


}

[Ken2k7]

Just remove it from the validation altogether.

 

HTML

<form name="frmContact" method="post">
                   <table cellpadding="0" cellspacing="0" border="0" width="100%">
                       <tr>
                            <td align="right" width="15%" class="label">Name:</td>
                            <td width="85%" ><input type="text" name="name" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_name"></span></td>
                        </tr>
                       <tr>
                           <td align="right" class="label">Phone:</td>
                            <td ><input type="text" name="phone" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_phone"></span></td>
                        </tr>
                       <tr>
                           <td align="right"  class="label">Email:</td>
                            <td ><input type="text" name="email" class="textfield"/></td>
                          <td > </td>
                            <td><span id="spn_email"></span></td>
                        </tr>
                       <tr>
                           <td align="right" valign="top" class="label">Message:</td>
                            <td ><textarea name="message" cols="20" rows="5" class="textarea"></textarea></td>
                          <td > </td>
                            <td></td>
                        </tr>
                       <tr>
                           <td align="right" valign="top" class="label"> </td>
                            <td ><input type="button" name="submit" id="submit" value="Submit" onclick="validate('frmContact', 'name', 'email', 'phone', 'CMS/cmsImages/approvedMark.gif', 'CMS/cmsImages/rejectMark.png');"/></td>
                          <td > </td>
                        </tr>
                    </table>
    </form> 

 

JavaScript

   // This runs the validation and updates the Page
   function runValidation(myField, MyReg, MyElementName){
      if(!myField.match(MyReg)){
         document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+rejectMK+"' width='12' height='12' />";
      }else{
         document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+apprvMK+"' width='12' height='12' />";
      }
   }

// Validation Filters
var emailReg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
var nameReg = /[A-Za-z\'\-]/;
var phoneReg = /[0-9\(\)\-\+ ]{7,16}/;

function validate(frmName, fieldName, fieldEmail, fieldPhone, apprvMK, rejectMK){
// Set Variables to hold values and followed by Element Name
   var name  = document.forms[frmName].elements[fieldName].value;
   var nameElementName  = document.forms[frmName].elements[fieldName].name;
   var emailAddress  = document.forms[frmName].elements[fieldEmail].value;
   var emailElementName  = document.forms[frmName].elements[fieldEmail].name
   var phone  = document.forms[frmName].elements[fieldPhone].value;
   var phoneElementName  = document.forms[frmName].elements[fieldPhone].name;
   
   runValidation(name, nameReg, nameElementName);
   runValidation(emailAddress, emailReg, emailElementName);
   runValidation(phone, phoneReg, phoneElementName);
}

[garethhall]

I know but that is the easy way out I am wanting my code to be as reusable as it can be. If I take it out and say I have another page that does need to validate those 2 fields then I would have to make a separate function or script.

[Ken2k7]

// Validation Filters
var emailReg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
var nameReg = /[A-Za-z\'\-]/;
var phoneReg = /[0-9\(\)\-\+ ]{7,16}/;

function validate(frmName, fieldName, fieldLastName, fieldEmail, fieldPhone, fieldFax, apprvMK, rejectMK){
// Set Variables to hold values and followed by Element Name
   var name  = document.forms[frmName].elements[fieldName].value;
   var nameElementName  = document.forms[frmName].elements[fieldName].name;
   var lastName  = document.forms[frmName].elements[fieldLastName].value;
   var lastNameElementName  = document.forms[frmName].elements[fieldLastName].name;
   var emailAddress  = document.forms[frmName].elements[fieldEmail].value;
   var emailElementName  = document.forms[frmName].elements[fieldEmail].name
   var phone  = document.forms[frmName].elements[fieldPhone].value;
   var phoneElementName  = document.forms[frmName].elements[fieldPhone].name;
   var fax  = document.forms[frmName].elements[fieldFax].value;
   var faxElementName  = document.forms[frmName].elements[fieldFax].name;
   
   // This runs the validation and updates the Page
   function runValidation(myField, MyReg, MyElementName){
      if(!myField.match(MyReg)){
         document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+rejectMK+"' width='12' height='12' />";
      }else{
         document.getElementById("spn_"+MyElementName).innerHTML = "<img src='"+apprvMK+"' width='12' height='12' />";
      }
   }
   
   runValidation(name, nameReg, nameElementName);
   if (lastName !== '') runValidation(lastName, nameReg, lastNameElementName);
   runValidation(emailAddress, emailReg, emailElementName);
   runValidation(phone, phoneReg, phoneElementName);
   if (fax !== '') runValidation(fax, phoneReg, faxElementName);
}

[.josh]

<script language="javascript">
function blah(a,b,c) {
  if (a == null) alert('a is null');
}
</script>

<a href='' onclick="blah(1,2,3);">a is not null</a><br/>
<a href='' onclick="blah(null,2,3);">a is null</a><br/>

[bibby]

'', undefined, null, 0, NaN are all in the "nothing family" , in that they fail to pass if

 

if(x){}

 

They sometimes == each other, but not never ===  ,

such as 

undefined == null

'' == false

0 == ''

 

NaN is neither true, false, or null, but is still a number