JavaScript Articles
3 Backslash Uses in JavaScript Strings
The skilled JavaScript programmer knows these 3 uses for the backslash character by heart. No need to think. The fingers type the backslash character seemingly automatically in response to the need.
Publishing JavaScript in email has an uncertainty, a gotcha: The software used to read the email may react unexpectedly to the script tag.
When a form has a dropdown list to select a year, the form creator often extends selections way into the future. Recently, I saw a form with a baby's "expected delivery date" dropdown list containing year selections for every year current to 12 years into the future.
Amazon Royalties Estimator on Your Web Pages
For your website: An attractive and useful calculator. Estimate your royalties from your Amazon publications.
Default Form Field Values Assigned After Form Submission
It's easy enough to provide default information in form fields. Simply use the value="..." attribute. Yet, that may not always be an appropriate way to do it.
Different Email Destinations For Different Form User Locations
I will show you how to send email to a different destination if the form user does not specify a certain geographic location.
Donation Payment Amount Fields
How to allow only one payment amount on a form to be submitted.
I'll show you how to prevent pretty much any JavaScript function from running more than once with a cookie.
Email Address Identical Check In Form
There several ways to make it more likely a form user will type an email address correctly. One is the method at Validating Form Field Email Addresses. Another is a system where the user must validate the address by clicking on a link in an email (or reply to it) sent to the address provided on the form.
A third method, the subject of this article, is to compare 2 email form fields. The user is required to type or paste the same address in both fields.
Importing JavaScript from an external file can be prudent — rather than embedding the JavaScript code in the web page.
Find Highest z-index and Lowest z-index,
To determine the highest CSS z-index and the lowest z-index on the page, the z-index range, use the JavaScript function zIndexRange()
Form text fields may themselves contain a prompt indicating what information is expected. When the field is clicked on, the prompt disappears.
Back in the "old" days, when some browsers did not understand JavaScript, the HTML comment tag was used to comment out the JavaScript code. Otherwise, the browser would print the code on the web page. ... Recently, however, we came full circle. The HTML comment tag is needed once more.
Several generators are incorporated into my personal portal page, the web page on my hard drive that is my browser's home page. One of those is an HTML entities generator. It's for those instances where I need to obfuscate some web page source code, yet have no need for high security.
Inserting An External JavaScript File Into JavaScript
When attempting to use document.write() to insert an external JavaScript file into a web page, the "script" tag within the document.write() statement can spawn an error. Here is a work-around.
JavaScript can do an instant check when a form is submitted and prevent the submission if required fields are empty, along with an appropriate message. No need to reload the form. Less hassle for the user.
JavaScript Validation Field Name Restrictions
When JavaScript uses a form field name to validate or otherwise manipulate the field's value, then form field name has certain restrictions.
Multiple Function Calls with One Onclick Attribute
Once in a while we receive questions like, "How do I run more than one JavaScript function with one onclick= or onsubmit= call?"
One Way to Block Form Submission Robots
They pollute forums, inundate email boxes, corrupt databases with loads of wrong information, and vie with legitimate traffic for use of the Internet. I don't know how to keep them off the Internet. But I can tell you about a way to block them from auto-submitting your forms.
A free password generator. Use here or copy the code and put it on your own web page.
Preventing Excessively Large Feedback/Contact Messages
Very large emails and feedback/contact messages are more likely to be ignored than short, succinct ones. I'll show you how to display a custom error message if the number of characters in the form user's message exceeds your specified limit. If the limit is not exceeded, there is no indication there was a limit at all.
Printing the Current Date with JavaScript
This JavaScript will print the current date on a web page.
'Processing' Message on Submit
How to prevent subsequent tap on submit button and let form user know their information is being processed.
When you need to generate a random number with JavaScript, the RandomNumber() function can be used. RandomNumber() expects two values, the minimum number and the maximum number and returns a random number within that range.
Running A JavaScript Function Every So Often
Sometimes, it is desirable to run a certain JavaScript function every so often on a web page. A clock update or an image rotation are possibilities.
Spamming You Through Your Own Forms
Are you getting spammed through your own web page forms? If not, remember willmaster.com for when it does happen. They have a solution.
Strings with Line Breaks in JavaScript
Strings containing literal line breaks can break JavaScript code. This article provides several ways to deal with line breaks when assigning strings to a variable and when writing strings with document.write() or document.writeln().
