Shows the usage of callback functions for checking a field : Validation : Form Control : JavaScript DHTML examples (example source code) Organized by topic

JavaScript DHTML
1. Ajax Layer
2. Data Type
3. Date Time
4. Development
5. Document
6. Event
7. Event onMethod
8. Form Control
9. GUI Components
10. HTML
11. Javascript Collections
12. Javascript Objects
13. Language Basics
14. Node Operation
15. Object Oriented
16. Page Components
17. Security
18. Style Layout
19. Table
20. Utilities
21. Window Browser
Java
Java Tutorial
Java Articles
Java Products
Java by API
C# / C Sharp
C# / CSharp Tutorial
ASP.Net
JavaScript Tutorial
JavaScript Reference
HTML / CSS
HTML CSS Reference
C / ANSI-C
C Tutorial
C++
C++ Tutorial
PHP
Python
SQL Server / T-SQL
Oracle PL / SQL
Oracle PL/SQL Tutorial
PostgreSQL
SQL / MySQL
MySQL Tutorial
VB.Net
VB.Net Tutorial
JavaScript DHTML » Form Control » Validation 
Shows the usage of callback functions for checking a field


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
  <title>Example 6</title>
  <style rel="stylesheet" type="text/css">
body, p, td, li, h1, h2, h3 font-family: "Lucida Grande", Verdana, Arial, Helvetica, Geneva, sans-serif; }
body, p, td, li, h2, h3     font-size: 12px; }
h2, h3    font-weight: bold; color:#323777; margin-bottom: 11px; }
h1          font-size:16px; font-weight: bold; color:#DB3259; margin-bottom: 3px; }
h2, h3      margin-top: 17px;  }

.header     font-weight: bold; color:#323777; margin-bottom: 11px; }
.headline  font-weight: bold; color:#323777}

p           margin-top: 14px; }

a           text-decoration: none; color:#323788}
a:hover     text-decoration: underline;           }
a.nav       text-decoration: none; color:#000000}
a.nav:hover text-decoration: underline;           }

pre         font-family:Courier New, Courier, monospace; font-size:12px; }
ul          list-style-type: square; margin-top: 2px;        }

td.header   color: #FFFFFF; background-color:#323777}
td.cell     background-color:#FFFFFF; }

input, select    border: 1px solid silver; }
input.error, select.error {padding-right: 16px; border: 1px solid red; background-color: #FFFCE2; background-image: url(validateimages/warning_obj.gif); background-position: right; background-repeat: no-repeat;}
input:focus, select:focus {border: 1px solid red; background-color:#EFEFEF;}
.mandatory  font-weight: bold; }
.comment    color: #BBBBBB; }

  </style>
    <script language="javascript">

function validateCompleteForm(objForm,strErrorClass){
return _validateInternal(objForm,strErrorClass,0);
};
function validateStandard(objForm,strErrorClass){
return _validateInternal(objForm,strErrorClass,1);
};
function _validateInternal(form,strErrorClass,nErrorThrowType){
var strErrorMessage="";var objFirstError=null;
if(nErrorThrowType==0){
strErrorMessage=(form.err)?form.err:_getLanguageText("err_form");
};
var fields=_GenerateFormFields(form);
for(var i=0;i<fields.length;++i){
var field=fields[i];
if(!field.IsValid(fields)){
field.SetClass(strErrorClass);
if(nErrorThrowType==1){
_throwError(field);
return false;
}else{
if(objFirstError==null){
objFirstError=field;
}
strErrorMessage=_handleError(field,strErrorMessage);
bError=true;
}
}else{
field.ResetClass();
}
};
if(objFirstError!=null){
alert(strErrorMessage);
objFirstError.element.focus();
return false;
};
return true;
};
function _getLanguageText(id){
objTextsInternal=new _jsVal_Language();
objTexts=null;
try{
objTexts=new jsVal_Language();
}catch(ignored){};
switch(id){
case "err_form":strResult=(!objTexts||!objTexts.err_form)?objTextsInternal.err_form:objTexts.err_form;break;
case "err_enter":strResult=(!objTexts||!objTexts.err_enter)?objTextsInternal.err_enter:objTexts.err_enter;break;
case "err_select":strResult=(!objTexts||!objTexts.err_select)?objTextsInternal.err_select:objTexts.err_select;break;
};
return strResult;
};
function _GenerateFormFields(form){
var arr=new Array();
for(var i=0;i<form.length;++i){
var element=form.elements[i];
var index=_getElementIndex(arr,element);
if(index==-1){
arr[arr.length]=new Field(element,form);
}else{
arr[index].Merge(element)
};
};
return arr;
};
function _getElementIndex(arr,element){
if(element.name){
var elementName=element.name.toLowerCase();
for(var i=0;i<arr.length;++i){
if(arr[i].element.name){
if(arr[i].element.name.toLowerCase()==elementName){
return i;
}
};
};
}
return -1;
};
function _jsVal_Language(){
this.err_form="Please enter/select values for the following fields:\n\n";
this.err_select="Please select a valid \"%FIELDNAME%\"";
this.err_enter="Please enter a valid \"%FIELDNAME%\"";
};
function Field(element,form){
this.type=element.type;
this.element=element;
this.exclude=element.exclude||element.getAttribute('exclude');
this.err=element.err||element.getAttribute('err');
this.required=_parseBoolean(element.required||element.getAttribute('required'));
this.realname=element.realname||element.getAttribute('realname');
this.elements=new Array();
switch(this.type){
case "textarea":
case "password":
case "text":
case "file":
this.value=element.value;
this.minLength=element.minlength||element.getAttribute('minlength');
this.maxLength=element.maxlength||element.getAttribute('maxlength');
this.regexp=this._getRegEx(element);
this.minValue=element.minvalue||element.getAttribute('minvalue');
this.maxValue=element.maxvalue||element.getAttribute('maxvalue');
this.equals=element.equals||element.getAttribute('equals');
this.callback=element.callback||element.getAttribute('callback');
break;
case "select-one":
case "select-multiple":
this.values=new Array();
for(var i=0;i<element.options.length;++i){
if(element.options[i].selected&&(!this.exclude||element.options[i].value!=this.exclude)){
this.values[this.values.length]=element.options[i].value;
}
}
this.min=element.min||element.getAttribute('min');
this.max=element.max||element.getAttribute('max');
this.equals=element.equals||element.getAttribute('equals');
break;
case "checkbox":
this.min=element.min||element.getAttribute('min');
this.max=element.max||element.getAttribute('max');
case "radio":
this.required=_parseBoolean(this.required||element.getAttribute('required'));
this.values=new Array();
if(element.checked){
this.values[0]=element.value;
}
this.elements[0]=element;
break;
};
};
Field.prototype.Merge=function(element){
var required=_parseBoolean(element.getAttribute('required'));
if(required){
this.required=true;
};
if(!this.err){
this.err=element.getAttribute('err');
};
if(!this.equals){
this.equals=element.getAttribute('equals');
};
if(!this.callback){
this.callback=element.getAttribute('callback');
};
if(!this.realname){
this.realname=element.getAttribute('realname');
};
if(!this.max){
this.max=element.getAttribute('max');
};
if(!this.min){
this.min=element.getAttribute('min');
};
if(!this.regexp){
this.regexp=this._getRegEx(element);
};
if(element.checked){
this.values[this.values.length]=element.value;
};
this.elements[this.elements.length]=element;
};
Field.prototype.IsValid=function(arrFields){
switch(this.type){
case "textarea":
case "password":
case "text":
case "file":
return this._ValidateText(arrFields);
case "select-one":
case "select-multiple":
case "radio":
case "checkbox":
return this._ValidateGroup(arrFields);
default:
return true;
};
};
Field.prototype.SetClass=function(newClassName){
if((newClassName)&&(newClassName!="")){
if((this.elements)&&(this.elements.length>0)){
for(var i=0;i<this.elements.length;++i){
if(this.elements[i].className!=newClassName){
this.elements[i].oldClassName=this.elements[i].className;
this.elements[i].className=newClassName;
}
}
}else{
if(this.element.className!=newClassName){
this.element.oldClassName=this.element.className;
this.element.className=newClassName;
}
};
}
};
Field.prototype.ResetClass=function(){
if((this.type!="button")&&(this.type!="submit")&&(this.type!="reset")){
if((this.elements)&&(this.elements.length>0)){
for(var i=0;i<this.elements.length;++i){
if(this.elements[i].oldClassName){
this.elements[i].className=this.elements[i].oldClassName;
}
else{
this.element.className="";
}
}
}else{
if(this.elements.oldClassName){
this.element.className=this.element.oldClassName;
}
else{
this.element.className="";
}
};
};
};
Field.prototype._getRegEx=function(element){
regex=element.regexp||element.getAttribute('regexp')
if(regex==null)return null;
retype=typeof(regex);
if(retype.toUpperCase()=="FUNCTION")
return regex;
else if((retype.toUpperCase()=="STRING")&&!(regex=="JSVAL_RX_EMAIL")&&!(regex=="JSVAL_RX_TEL")
&&!(regex=="JSVAL_RX_PC")&&!(regex=="JSVAL_RX_ZIP")&&!(regex=="JSVAL_RX_MONEY")
&&!(regex=="JSVAL_RX_CREDITCARD")&&!(regex=="JSVAL_RX_POSTALZIP"))
{
nBegin=0;nEnd=0;
if(regex.charAt(0)=="/")nBegin=1;
if(regex.charAt(regex.length-1)=="/")nEnd=0;
return new RegExp(regex.slice(nBegin,nEnd));
}
else{
return regex;
};
};
Field.prototype._ValidateText=function(arrFields){
if((this.required)&&(this.callback)){
nCurId=this.element.id?this.element.id:"";
nCurName=this.element.name?this.element.name:"";
eval("bResult = "+this.callback+"('"+nCurId+"', '"+nCurName+"', '"+this.value+"');");
if(bResult==false){
return false;
};
}else{
if(this.required&&!this.value){
return false;
};
if(this.value&&(this.minLength&&this.value.length<this.minLength)){
return false;
};
if(this.value&&(this.maxLength&&this.value.length>this.maxLength)){
return false;
};
if(this.regexp){
if(!_checkRegExp(this.regexp,this.value))
{
if(!this.required&&this.value){
return false;
}
if(this.required){
return false;
}
}
else
{
return true;
};
};
if(this.equals){
for(var i=0;i<arrFields.length;++i){
var field=arrFields[i];
if((field.element.name==this.equals)||(field.element.id==this.equals)){
if(field.element.value!=this.value){
return false;
};
break;
};
};
};
if(this.required){
var fValue=parseFloat(this.value);
if((this.minValue||this.maxValue)&&isNaN(fValue)){
return false;
};
if((this.minValue)&&(fValue<this.minValue)){
return false;
};
if((this.maxValue)&&(fValue>this.maxValue)){
return false
};
};
}
return true;
};
Field.prototype._ValidateGroup=function(arrFields){
if(this.required&&this.values.length==0){
return false;
};
if(this.required&&this.min&&this.min>this.values.length){
return false;
};
if(this.required&&this.max&&this.max<this.values.length){
return false;
};
return true;
};
function _handleError(field,strErrorMessage){
var obj=field.element;
strNewMessage=strErrorMessage+((field.realname)?field.realname:((obj.id)?obj.id:obj.name))+"\n";
return strNewMessage;
};
function _throwError(field){
var obj=field.element;
switch(field.type){
case "text":
case "password":
case "textarea":
case "file":
alert(_getError(field,"err_enter"));
try{
obj.focus();
}
catch(ignore){}
break;
case "select-one":
case "select-multiple":
case "radio":
case "checkbox":
alert(_getError(field,"err_select"));
break;
};
};
function _getError(field,str){
var obj=field.element;
strErrorTemp=(field.err)?field.err:_getLanguageText(str);
idx=strErrorTemp.indexOf("\\n");
while(idx>-1){
strErrorTemp=strErrorTemp.replace("\\n","\n");
idx=strErrorTemp.indexOf("\\n");
};
return strErrorTemp.replace("%FIELDNAME%",(field.realname)?field.realname:((obj.id)?obj.id:obj.name));
};
function _parseBoolean(value){
return !(!value||value==0||value=="0"||value=="false");
};
function _checkRegExp(regx,value){
switch(regx){
case "JSVAL_RX_EMAIL":
return((/^[a-zA-Z???]+([\.-]?[a-zA-Z???]+)*@[a-zA-Z???]+([\.-]?[a-zA-Z???]+)*(\.\w{2,5})+$/).test(value));
case "JSVAL_RX_TEL":
return((/^1?[\-]?\(?\d{3}\)?[\-]?\d{3}[\-]?\d{4}$/).test(value));
case "JSVAL_RX_PC":
return((/^[a-z]\d[a-z]?\d[a-z]\d$/i).test(value));
case "JSVAL_RX_ZIP":
return((/^\d{5}$/).test(value));
case "JSVAL_RX_MONEY":
return((/^\d+([\.]\d\d)?$/).test(value));
case "JSVAL_RX_CREDITCARD":
return(!isNaN(value));
case "JSVAL_RX_POSTALZIP":
if(value.length==6||value.length==7)
return((/^[a-zA-Z]\d[a-zA-Z?\d[a-zA-Z]\d$/).test(value));
if(value.length==5||value.length==10)
return((/^\d{5}(\-\d{4})?$/).test(value));
break;
default:
return(regx.test(value));
};
};

    </script>
    
    <script language="JavaScript">
      //---- example of a callback function
      function validateValue2(id, name, value)
      {
          objValue1 = document.getElementById("value1");
          
          if (value*objValue1.value > 10) {
             return true
          }
          return false;
      }
    </script>
</head>

<body style="margin: 10px 10px 10px 10px">
  <h1>Example 6</h1>
    <h2>Test-Form:</h2>
    This form is using a callback function for checking the "value 2" field. 
  In a javascript function the value is multiplied with the value of the "value 1" field. 
  If the result is greater than 10 the field is valid.<br><br>
  <table border="0">
        <tr>
            <td>
                <form name="testform" method="post" onSubmit="return validateStandard(this, 'error');">
                <table>
                    <tr>
                        <td class="mandatory">Value 1:</td>
                        <td><input type="text" name="value1" id="value1" required="1" regexp="/^\d*$/" size="40"></td>
                        <td class="comment">//--- Only digits allowed</td>
                    </tr>
                    <tr>
                        <td class="mandatory">Value 2:</td>
                        <td><input type="text" name="value2" id="value2" required="1" callback="validateValue2"></td>
                        <td class="comment">//--- field is valid if the value multiplied with the value 1 is greater than 10</td>
                    </tr>
                    <tr>
                        <td>&nbsp;</td>
                        <td><input type="submit" value="Submit"></td>
                    </tr>
                </table>
                </form>

            </td>
        </tr>
    </table>
</body>
</html>
           
       
jsval_1.3.4.zip( 46 k)
Related examples in the same category
1. Form validation: Not Empty, Valid Radio, is Number, string length, EMail Address
2. Validate an input field with minimum and maximum values
3. Validate an field with a maximum number of characters
4. Phone Number Validation
5. Creating Reusable Validation Code
6. Credit Card Validation
7. Money Format
8. Validating User Input
9. Validate email address
10. Validate a number
11. TextField input length validator
12. Password field validator
13. TextField validator: email, IP address and URL
14. Must be at least 3 characters and not more than 8
15. Only characters are allowed
16. Can be empty
17. Must be a valid email address
18. ComboBox(list box): Must be selected one
19. InputBox: value must be between 10 and 90
20. Not stop when the first failed validation is encountered
21. A CSS is used to highlight the fields which failed to validate
22. Need to select a file
23. A simple form with two passwords that must have the same value
24. Javascript validation framework
25. Form validator library
Home | Contact Us
Copyright 2003 - 07 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.