Now, we will learn how to perform validations at the client side with the help of JavaScript/jQuery.
The main advantage of this approach is given below.
- We are able to improve the performance of our web application, since it runs in the browser itself and it is quick as well.
 
In this article, I will demonstrate
- How to validate alphanumeric entry in input textbox
For this purpose, use isAlphaNumericContents(), which is mentioned below.
 - How to validate decimal values entry in input textbox
For this purpose, use CheckValidDecimalAmount (), which is mentioned below.
 - How to validate email id entry in input textbox
For this purpose, use validateUpdatedEmail (), which is mentioned below. 
 
Now, let us see with the code snippets given below. 
- <div class="divSandipPatilContents"> <input type="text" id="trasanctionNumber" /> <input type="text" id="totalPaidAmount" /> <input type="text id=" patienEmailID " />  
 -   
 - <button ng-click="ValidateData(); ">Validate All Data</button>  
 -   
 - </div>  
 
 
Now, use the code given below in your controller.js. 
- $scope.ValidateData = function() {  
 -     IsValid();  
 - }  
 -   
 - function IsValid() {  
 -     var flag = true;  
 -     var errorMessages = [];  
 -     var trasanctionNumber = angular.element("#trasanctionNumber").val();  
 -     var amountPaid = angular.element("#totalPaidAmount").val();  
 -     var updatedEmailID = angular.element("#patienEmailID").val();  
 -     if (!isAlphaNumericContents(trasanctionNumber)) {  
 -         errorMessages.push("Please Enter Alphanumeric Transaction Number.\n");  
 -         flag = false;  
 -     }  
 -     if (!CheckValidDecimalAmount(amountPaid)) {  
 -         errorMessages.push("Please Enter Valid Total Paid Amount.\n");  
 -         flag = false;  
 -     }  
 -     if (!validateUpdatedEmail(updatedEmailID)) {  
 -         errorMessages.push("Please Enter Patient's Valid Email ID.");  
 -         flag = false;  
 -     }  
 -     $scope.txberrMsg = errorMessages;  
 -     return flag;  
 - }  
 -   
 - function isAlphaNumericContents(strContents) {  
 -     var cde, i, l;  
 -     for (i = 0, l = strContents.length; i < l; i++) {  
 -         cde = strContents.charCodeAt(i);  
 -         if (!(cde > 47 && cde < 58) && !(cde > 64 && cde < 91) && !(cde > 96 && cde < 123)) {  
 -             return false;  
 -         }  
 -     }  
 -     return true;  
 - };  
 -   
 - function CheckValidDecimalAmount(amountPaid) {  
 -     if (!(/^[-+]?\d*\.?\d*$/.test(amountPaid))) {  
 -         return false;  
 -     }  
 -     return true;  
 - }  
 -   
 - function validateUpdatedEmail(updatedEmailID) {  
 -     var regexInfo = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;  
 -     return regexInfo.test(updatedEmailID);  
 - }   
 
 
The image given below demonstrates how all the above validations are being fired in the Browser.
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