Validate email address using javascript

Javascript interview questions

Validate email address using javascript

Kris Kimcil 05.52 Komentar

• One of the famous interview question in JavaScript : how to validate email address in JavaScript.
• In order to validate a text field of HTML we need a JavaScript function.
• On submit form we need to call a java script function to validate all fields in the form also known as client side validation.
• Now on form submit we need to check email text field and validate it whether entered email is in correct format or not for ex: instanceofjava@gmail.com. 

JavaScript program for email validation:

1. <!DOCTYPE html>
2. <html>
3. <head>
4. <script>
5. function validateEmailForm() {
6.     var x = document.forms["Form_Name"]["txt_email"].value;
7.     var atpos = x.indexOf("@");
8.     var dotpos = x.lastIndexOf(".");
9.     if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length) {
10.         alert("Not a valid e-mail address");
11.         return false;
12.     }
13. }
14. </script>
15. </head>
16.  
17. <body>
18. <form name="Form_Name" action="User_email_validation.jsp" onsubmit="return
19. validateEmailForm();" method="post">
20. Email: <input type="text" name="txt_email">
21. <input type="submit" value="Submit">
22. </form>
23. </body>
24.  
25. </html>

Validate email in java-script using regular expression: on submit form validation

1. <!DOCTYPE html>
2. <html>
3. <head>
4. <script>
5. function validateEmailForm() {
6.     var email = document.forms["Form_Name"]["txt_email"].value;
7.   
8.  var re = /\S+@\S+\.\S+/;
9.     return re.test(email);
10.   
11.     }
12. }
13. </script>
14. </head>
15.  
16. <body>
17. <form name="Form_Name" action="User_email_validation.jsp" onsubmit="return
18. validateEmailForm();" method="post">
19. Email: <input type="text" name="txt_email">
20. <input type="submit" value="Submit">
21. </form>
22. </body>
23.  
24. </html>

HTML 5 Email validation:

1. <form>
2. <input type="email" placeholder="Enter your email">
3. <input type="submit" value="Submit">
4. </form>

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How to get table cell data using JavaScript

Javascript interview questions

How to get table cell data using JavaScript

Kris Kimcil 05.17 Komentar

How to get table row data in javascript:

• When we are working with HTML tables we will get a scenario like to get whole table rows data, or table td values , table cell value in JavaScript.
• For that we need to read the table by using JavaScript.
• lets see example on get table cell data using java script.
• Before that lets see how to read the data of table using JavaScript
• To find number of rows of a table by using table id in JavaScript.

1. var numberOfrows=document.getElementById("tableData").rows.length;

• Get number of cells or number of tds inside each tr (table row)

1. var numberoftds = document.getElementById("tableData").rows[0].cells.length;

• JavaScript get table row values get table td data

1. var numberoftds = document.getElementById("tableData").rows[0].cells.item(0).innerHTML;

Example on get table each row data using javascript:

1. <script type="text/javascript">
2. function checkFun() {
3. 
   
4. var n1 = document.getElementById("tableData").rows.length;
5. 
   
6. var i=0,j=0;
7. var str="";
8.  
9. for(i=0; i<n1;i++){
10.  
11. var n2 = document.getElementById("tableData").rows[i].cells.length;
12.  
13. for(j=0; j<n2;j++){
14.  
15. var x=document.getElementById("tableData").rows[i].cells.item(j).innerHTML;\
16.  
17.     str=str+x+":";
18.  
19. }
20. str=str+"#";
21.    
22. }
23.    document.getElementById("tablecontent").innerHTML=str;
24. 
    
25.    
26. }
27. </script>

1. <body onload="checkFun()">
2.  
3. <table id="tableData" border="1">
4.     <tr>
5.         <td >37</td>
6.         <td >46</td>
7.         <td >3</td>
8.         <td >64</td>
9.     </tr>
10.     <tr>
11.         <td >10</td>
12.         <td >4</td>
13.         <td >7</td>
14.         <td >21</td>
15.     </tr>
16.     
17. </table>
18. <p id="tablecontent" ></p>
19.  </body>

• Here in this example on page loading we called the JavaScript function
• For that used body onload="func()" .
• Practice this example in your System.

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