JS and barcode generation

by zhangxinxu from https://www.zhangxinxu.com/wordpress/?p=10402 Xin Space-Xin Life

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Bar code picture

1. Use this Github project

JS generates barcode: https://github.com/lindell/JsBarcode

The official provides a real-time barcode generator, click here to visit.

If the above address cannot be accessed, you can also access this Chinese version . I translated the official generator and put it on my server to avoid the inability to access the above address after N years (I have stepped on the pit many times) .

JS barcode generator page screenshot

2. How to use it?

It is still very convenient to use.

First, in the first step, place the corresponding image elements in the page where the barcode needs to be displayed, and support SVG, Canvas or IMG elements.

 <svg id="barcode"></svg> <!-- or --> <canvas id="barcode"></canvas> <!-- or --> <img id="barcode"/>

Then, in the second step, import the JS file:

 <script src="./JsBarcode.all.min.js"></script>

Finally, in the third step, execute the corresponding JS code, for example:

 JsBarcode("#barcode", "iam zhangxinxu");

and you’re done.

Seeing is believing, you can click here: JSBarcode The most basic barcode using demo

QR code use demo


The JsBarcode API is still very rich, supports customization of various styles, and supports various barcode encodings.

See the table below for style customization parameters:

optional parameter Defaults type
format "auto" (CODE128) String
width 2 Number
height 100 Number
displayValue true Boolean
text undefined String
fontOptions "" String
font "monospace" String
textAlign "center" String
textPosition "bottom" String
textMargin 2 Number
fontSize 20 Number
background "#ffffff" String (CSS color)
lineColor "#000000" String (CSS color)
margin 10 Number
marginTop undefined Number
marginBottom undefined Number
marginLeft undefined Number
marginRight undefined Number
valid function(valid){} Function

The knowledge about barcodes can be found in this encyclopedia . At present, it is mainly used in commodities. When checking out in supermarkets, scan the code, drop it, and the price will come out.

Although barcodes are very useful in life, it seems that they are not as good as QR codes in the Internet field. Why? Is it really useless in the web?

3. What is the use of barcodes in the Web?

We mostly use QR codes to hide information on the Web, because it can contain more information, including Chinese.

The barcode Chinese is not supported, and can only be relatively basic Unicode characters such as English letters and numbers.

However, the barcode also has advantages, that is, the graphic of the barcode can be understood as a one-dimensional plane structure, and the shape is simpler, while the two-dimensional code is a two-dimensional graphic structure, and the shape is more complicated.

There is an advantage to the simple shape, which can be buried in information more covertly.

For example, if we make the height of the barcode small enough, the barcode behaves like a dotted line.

For example, the following figure shows the performance of 10 Arabic numerals when the height of the barcode generator page is adjusted to 10:

Bar code effect

If the height is only 1px, and then tile it horizontally, it is like a dotted line with a sense of design. For example, the dotted line below this sentence in this article actually hides my name.

Of course, it is simple in theory, but it is still difficult to identify in practice. Once the loop is tiled, it will be difficult to identify where is the head and where is the tail, and you need to think of other methods.

When I talked about the “Cicada Principle” before (the article is here ), I talked about the strategy of CSS to create a random striped background.

random shading background

In fact, there are many similarities between the stripes and barcodes that look random. If we hide the stripes of the barcode in a random background in some way, is it very hidden, but at the same time it is not easy What about the broken way of adding a watermark?

4. JS generates QR code

By the way, how to use JS to generate QR code is this project: https://github.com/davidshimjs/qrcodejs

It is very simple to use, import JS, and then execute the JavaScript code similar to the following and it will be OK:

 <div id="qrcode"></div> <script> new QRCode(document.getElementById("qrcode"), "https://www.zhangxinxu.com"); </script>

I also made an online QR code generator in the early years, which can be accessed here: Online QR Code Conversion Widget

Very concise and easy to use.

QR code generation screenshot

V. Concluding remarks

Wow, he seemed to have talked a lot, but when he looked up, he didn’t seem to have said much.

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There is a huge amount of stock, and it can be updated for ten years. If you have enough, you may not read the novels I wrote, but this collection is not to be missed. Click the link above, and then click on it.

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This article is an original article, welcome to share, do not reprint in full text, if you really like it, you can collect it, it will never expire, and will update knowledge points and correct errors in time, and the reading experience will be better.

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