How to evaluates a string in JavaScript?

The eval() function evaluates a string and executes it as if it was script code.

Syntax
eval(string) 

Parameter: string Required.
Description: The string to be evaluated

Example
In this example we use eval() on some strings and see what it returns:

<script type="text/javascript">
eval("x=10;y=20;document.write(x*y)");
document.write("<br />");
document.write(eval("2+2"))
document.write("<br />");
var x=10
document.write(eval(x+17))
document.write("<br />")
</script>

The output of the code above will be:
200
4
27

Final code and demo is here
<!DOCTYPE html><html><head><title>Online HTML Editor - webspeckle.com</title></head><body><h3>How to evaluates a string in JavaScript?</h3><script type="text/javascript">eval("x=10;y=20;document.write(x*y)") document.write("<br />"); document.write(eval("2+2")) document.write("<br />"); var x=10 document.write(eval(x+17)) document.write("<br />") </script></body></html>
Demo

Get today's date and time in JavaScript

The Date() method returns today's date and time.

Syntax: Date()

Example
In this example we will print today's date and time:

<script type="text/javascript">
document.write(Date())
</script>

The output of the code above will be:

Thu Jul 27 2017 23:23:42 GMT+0530 (India Standard Time)

Final code and demo is here
<!DOCTYPE html><html><head><title>Online HTML Editor - webspeckle.com</title></head><body><h3>Get today's date and time in JavaScript</h3><script type="text/javascript">document.write(Date()) </script> </body></html>
Demo

Convert Boolean to string in Java

By using Boolean.toString() this method to covert Boolean to string in Java. This method accepts the boolean argument and converts it into an equivalent String value.

boolean status = false;
String str = Boolean.toString(status);
System.out.println("String value of 'status' is: "+str);

Form validation using JavaScript

Parsley is a javascript form validation library. It helps you provide your users with feedback on their form submission before sending it to your server. It saves you bandwidth, server load and it saves time for your users.

Javascript form validation is not necessary, and if used, it does not replace strong backend server validation.

That's why Parsley is here: to let you define your general form validation, implement it on the backend side, and simply port it frontend-side, with maximum respect to user experience best practices.

Basic installation
Parsley relies on jQuery (>= 1.8), and it will need to be included before including Parsley.
 Then, you can either use parsley.js unminified file or parsley.min.js minified one. These files and extras are available here.

Finally, add data-parsley-validate to each <form> you want to be validated.

That would look pretty much like this:

<script src="jquery.js"></script>
<script src="parsley.min.js"></script>

<form id="form">
...
</form>

<script>
  $('#form').parsley();
</script>

Final code and demo is here
<!DOCTYPE html><html> <head> <title>Online HTML Editor - webspeckle.com</title> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css"/> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/parsley.js/2.7.2/parsley.min.js"></script> <style> .validate { margin-top: 10px; } .invalid-form-error-message { margin-top: 10px; padding: 5px; } .invalid-form-error-message.filled { border-left: 2px solid #E74C3C; } p.parsley-success { color: #468847; background-color: #DFF0D8; border: 1px solid #D6E9C6; } p.parsley-error { color: #B94A48; background-color: #F2DEDE; border: 1px solid #EED3D7; } ul.parsley-errors-list { list-style: none; color: #E74C3C; padding-left: 0; margin: 0px;/* By SRJ */ padding: 0px;/* By SRJ */ } input.parsley-error, textarea.parsley-error, select.parsley-error { background: #FAEDEC; border: 1px solid #E85445; } .btn-group .parsley-errors-list { display: none; } </style> </head> <body> <div class="container"> <h3>Form validation using JavaScript</h3><br/> <form id="demo-form" data-parsley-validate="" class="form-horizontal"> <div class="form-group"> <label for="fullname" class="control-label col-xs-4" >Full Name * :</label> <div class="col-xs-8"> <input class="form-control" name="fullname" required="" type="text"/> </div></div><div class="form-group"> <label for="email" class="control-label col-xs-4" >Email * :</label> <div class="col-xs-8"> <input class="form-control" name="email" data-parsley-trigger="change" required="" type="email"/> </div></div><div class="form-group"> <label for="gender" class="control-label col-xs-4">Gender *:</label> <div class="col-xs-8"> <div> M: <input name="gender" id="genderM" value="M" required="" type="radio"/> F: <input name="gender" id="genderF" value="F" type="radio"/> </div></div></div><div class="form-group"> <label for="hobbies" class="control-label col-xs-4">Hobbies (Optional, but 2 minimum):</label> <div class="col-xs-8 "> <div> <input checked name="hobbies[]" id="hobby1" value="ski" data-parsley-mincheck="2" type="checkbox"/> Skiing<br> <input name="hobbies[]" id="hobby2" value="run" type="checkbox"/> Running<br> <input name="hobbies[]" id="hobby3" value="eat" type="checkbox"/> Eating<br> <input name="hobbies[]" id="hobby4" value="sleep" type="checkbox"/> Sleeping<br> <input name="hobbies[]" id="hobby5" value="read" type="checkbox"/> Reading<br> <input name="hobbies[]" id="hobby6" value="code" type="checkbox"/> Coding </div></div></div><div class="form-group"> <label for="heard" class="control-label col-xs-4">Heard about us via *:</label> <div class="col-xs-8"> <select id="heard" required=""> <option value="">Choose..</option> <option value="press">Press</option> <option value="net">Internet</option> <option value="mouth">Word of mouth</option> <option value="other">Other..</option> </select> </div></div><div class="form-group"> <div class="col-xs-offset-4 col-xs-8"> <input class="btn btn-default" value="validate" type="submit"/> </div></div></form></div></body></html>
Demo

Get Unicode of the character at a specified position

The charCodeAt() method returns the Unicode of the character at a specified position.

stringObject.charCodeAt(index)

Parameter: index Required
Description: A number representing a position in the string

Note: The first character in the string is at position 0.

Example
In the string "Hello world!", we will return the Unicode of the character at position 1:

<script type="text/javascript">
var str="Hello world!"
document.write(str.charCodeAt(1))
</script>

The output of the code above will be:
101

Final code and demo is here
<!DOCTYPE html><html><head><title>Online HTML Editor - webspeckle.com</title></head><body><h3>Get Unicode of the character at a specified position</h3><script type="text/javascript">var str="webspeckle.com" document.write(str.charCodeAt(4)) </script> </body></html>
Demo

How to get the character at a specified position?

In JavaScript the charAt() method returns the character at a specified position.

stringObject.charAt(index)

Parameter: index
Description: Required. A number representing a position in the string

Note: The first character in the string is at position 0.

Example
In the string "Hello world!", we will return the character at position 1:

<script type="text/javascript">var str="Hello world!"
document.write(str.charAt(1))
</script>

The output of the code above will be:

e

Final code and demo is here
<!DOCTYPE html><html><head><title>Online HTML Editor - webspeckle.com</title></head><body><h3>How to get the character at a specified position?</h3><script type="text/javascript">var str="webspecle.com" document.write(str.charAt(6))</script></body></html>
Demo

Get value of a number rounded upwards

The ceil() method returns the value of a number rounded UPWARDS to the nearest integer.

Math.ceil(x)

'x' is required and should be a number

In the following example we will use the ceil() method on different numbers:

<script type="text/javascript">document.write(Math.ceil(0.60) + "<br />")
document.write(Math.ceil(0.40) + "<br />")
document.write(Math.ceil(5) + "<br />")
document.write(Math.ceil(5.1) + "<br />")
document.write(Math.ceil(-5.1) + "<br />")
document.write(Math.ceil(-5.9))
</script>

The output of the code above will be:
1
1
5
6
-5
-5

Final code and demo is here
<!DOCTYPE html><html><head><title>Online HTML Editor - webspeckle.com</title></head><body><h3>Get value of a number rounded upwards</h3><script type="text/javascript">document.write(Math.ceil(0.60) + "<br />") document.write(Math.ceil(0.40) + "<br />") document.write(Math.ceil(5) + "<br />") document.write(Math.ceil(5.1) + "<br />") document.write(Math.ceil(-5.1) + "<br />") document.write(Math.ceil(-5.9)) </script></body></html>
Demo