gen_validation.js

A JavaScript function to make your form validations a breeze!

/* 
    This is the source code for the validation function. 
    Add the following code just after the </HEAD> in the files where the 
    generalised validation functionality is required. 
    <SCRIPT language="JavaScript1.2" src="gen_validation.js"></SCRIPT> 
*/ 

    /* 
    *   File : gen_validation.js 
    *     
    *   Author : Prasanth M J 
    *   
    *   CreativeProgrammers.com - 
	*	Turn your Programming Expertise into Achievements!
    *   Visit http://www.creativeprogrammers.com 
    *     
    *   Email : [e-mail]
    */ 
//---------------------------------EMail Check ------------------------------------ 

/*  checks the validity of an email address entered 
*   returns true or false 
*   
*/ 

function validateEmail(email)
{
// a very simple email validation checking. 
// you can add more complex email checking if it helps 
    var splitted = email.match("^(.+)@(.+)$");
    if(splitted == null) return false;
    if(splitted[1] != null )
    {
      var regexp_user=/^\"?[\w-_\.]*\"?$/;
      if(splitted[1].match(regexp_user) == null) return false;
    }
    if(splitted[2] != null)
    {
      var regexp_domain=/^[\w-\.]*\.[A-Za-z]{2,4}$/;
      if(splitted[2].match(regexp_domain) == null) 
      {
	    var regexp_ip =/^\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\]$/;
	    if(splitted[2].match(regexp_ip) == null) return false;
      }// if
      return true;
    }
return false;
}

/* function validateData 
*  Checks each field in a form 
*  Called from validateForm function 
*/ 
function validateData(strValidateStr,objValue,strError) 
{ 
    var epos = strValidateStr.search("="); 
    var  command  = ""; 
    var  cmdvalue = ""; 
    if(epos >= 0) 
    { 
     command  = strValidateStr.substring(0,epos); 
     cmdvalue = strValidateStr.substr(epos+1); 
    } 
    else 
    { 
     command = strValidateStr; 
    } 

    switch(command) 
    { 
        case "req": 
        case "required": 
         { 
           if(eval(objValue.value.length) == 0) 
           { 
              if(!strError || strError.length ==0) 
              { 
                strError = objValue.name + " : Required Field"; 
              }//if 
              alert(strError); 
              return false; 
           }//if 
           break;             
         }//case required 
        case "maxlength": 
        case "maxlen": 
          { 
             if(eval(objValue.value.length) >  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = objValue.name + " : "+cmdvalue+" characters maximum "; 
               }//if 
               alert(strError + "\n[Current length = " + objValue.value.length + " ]"); 
               return false; 
             }//if 
             break; 
          }//case maxlen 
        case "minlength": 
        case "minlen": 
           { 
             if(eval(objValue.value.length) <  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = objValue.name + " : " + cmdvalue + " characters minimum  "; 
               }//if               
               alert(strError + "\n[Current length = " + objValue.value.length + " ]"); 
               return false;                 
             }//if 
             break; 
            }//case minlen 
        case "alnum": 
        case "alphanumeric": 
           { 
              var charpos = objValue.value.search("[^A-Za-z0-9]"); 
              if(objValue.value.length > 0 &&  charpos >= 0) 
              { 
               if(!strError || strError.length ==0) 
                { 
                  strError = objValue.name+": Only alpha-numeric characters allowed "; 
                }//if 
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break; 
           }//case alphanumeric 
        case "num": 
        case "numeric": 
           { 
              var charpos = objValue.value.search("[^0-9]"); 
              if(objValue.value.length > 0 &&  charpos >= 0) 
              { 
                if(!strError || strError.length ==0) 
                { 
                  strError = objValue.name+": Only digits allowed "; 
                }//if               
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break;               
           }//numeric 
        case "alphabetic": 
        case "alpha": 
           { 
              var charpos = objValue.value.search("[^A-Za-z]"); 
              if(objValue.value.length > 0 &&  charpos >= 0) 
              { 
                  if(!strError || strError.length ==0) 
                { 
                  strError = objValue.name+": Only alphabetic characters allowed "; 
                }//if                             
                alert(strError + "\n [Error character position " + eval(charpos+1)+"]"); 
                return false; 
              }//if 
              break; 
           }//alpha 
        case "email": 
          { 
               if(!validateEmail(objValue.value)) 
               { 
                 if(!strError || strError.length ==0) 
                 { 
                    strError = objValue.name+": Enter a valid Email address "; 
                 }//if                                               
                 alert(strError); 
                 return false; 
               }//if 
           break; 
          }//case email 
        case "lt": 
        case "lessthan": 
         { 
            if(isNaN(objValue.value)) 
            { 
              alert(objValue.name+": Should be a number "); 
              return false; 
            }//if 
            if(eval(objValue.value) >=  eval(cmdvalue)) 
            { 
              if(!strError || strError.length ==0) 
              { 
                strError = objValue.name + " : value should be less than "+ cmdvalue; 
              }//if               
              alert(strError); 
              return false;                 
             }//if             
            break; 
         }//case lessthan 
        case "gt": 
        case "greaterthan": 
         { 
            if(isNaN(objValue.value)) 
            { 
              alert(objValue.name+": Should be a number "); 
              return false; 
            }//if 
             if(eval(objValue.value) <=  eval(cmdvalue)) 
             { 
               if(!strError || strError.length ==0) 
               { 
                 strError = objValue.name + " : value should be greater than "+ cmdvalue; 
               }//if               
               alert(strError); 
               return false;                 
             }//if             
            break; 
         }//case greaterthan 
        case "regexp": 
         { 
            if(!objValue.value.match(cmdvalue)) 
            { 
              if(!strError || strError.length ==0) 
              { 
                strError = objValue.name+": Invalid characters found "; 
              }//if                                                               
              alert(strError); 
              return false;                   
            }//if 
           break; 
         }//case regexp 
        case "dontselect": 
         { 
            if(objValue.selectedIndex == null) 
            { 
              alert("BUG: dontselect command for non-select Item"); 
              return false; 
            } 
            if(objValue.selectedIndex == eval(cmdvalue)) 
            { 
             if(!strError || strError.length ==0) 
              { 
              strError = objValue.name+": Please Select one option "; 
              }//if                                                               
              alert(strError); 
              return false;                                   
             } 
             break; 
         }//case dontselect 
    }//switch 
    return true; 
} 

/* 
* function validateForm 
* the function that can be used to validate any form 
* returns false if the validation fails; true if success 
* arguments : 
*   objFrm     : the form object 
*   arrObjDesc : an array of objects describing the validations to conduct on each 
*        input item. 
*          The array should consist of one object per input item in the order the input 
*          elements are present in the form. Each object consist of zero or more validation 
*          objects. Each of these validation object is a pair consisting of the validation 
*          descriptor string and an optional Error message. 
*/ 

function validateForm(objFrm,arrObjDesc) 
{ 
 for(var itrobj=0; itrobj < arrObjDesc.length; itrobj++) 
 { 
   if(objFrm.elements.length <= itrobj) 
   { 
        alert("BUG: Obj descriptor for a non existent form element"); 
        return false; 
   }//if 
   for(var itrdesc=0; itrdesc < arrObjDesc[itrobj].length ;itrdesc++) 
   { 
      if(validateData(arrObjDesc[itrobj][itrdesc][0], 
                 objFrm[itrobj],arrObjDesc[itrobj][itrdesc][1]) == false) 
       { 
	     objFrm[itrobj].focus();
         return false; 
       }//if 
   }//for 
 }//for 
}