CODEWITHSUNDEEP
javascriptjqueryhtmlunicodehex
Hristo
Hristo

Reputation: 46537

How do I get the unicode/hex representation of a symbol out of the HTML using JavaScript/jQuery?

Say I have an element like this...

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mo class="symbol">α</mo>
</math>

Is there a way to get the unicode/hex value of alpha α, &#x03B1, using JavaScript/jQuery? Something like...

$('.symbol').text().unicode(); // I know unicode() doesn't exist
$('.symbol').text().hex(); // I know hex() doesn't exist

I need &#x03B1 instead of α and it seems like anytime I insert &#x03B1 into the DOM and try to retrieve it right away, it gets rendered and I can't get &#x03B1 back; I just get α.

Upvotes: 27

Views: 34265

Answers (4)

Matas Vaitkevicius
Matas Vaitkevicius

Reputation: 61479

If you would try to convert Unicode character out of BMP (basic multilingual plane) in ways above - you are up for a nasty surprise. Characters out of BMP are encoded as multiple UTF16 values for example:

"🔒".length = 2 (one part for shackle one part for lock base :) )

so "🔒".charCodeAt(0) will give you 55357 which is only 'half' of number while "🔒".charCodeAt(1) will give you 56594 which is the other half.

To get char codes for those values you might wanna use use following string extension function

String.prototype.charCodeUTF32 = function(){   
    return ((((this.charCodeAt(0)-0xD800)*0x400) + (this.charCodeAt(1)-0xDC00) + 0x10000));
};

you can also use it like this 

"&#x"+("🔒".charCodeUTF32()).toString(16)+";"

to get html hex codes.

Hope this saves you some time.

Upvotes: 18

chings228
chings228

Reputation: 1889

for example in case you need to convert this hex code to unicode

e68891e4bda0e4bb96

  1. pick two character time by time ,
  2. if the dec ascii code is over 127 , add a % before

  3. return url decode string

    function hex2a(hex) { var str = ''; for (var i = 0; i < hex.length; i += 2){

        var dec = parseInt(hex.substr(i, 2), 16);
    character = String.fromCharCode(dec);


    if (dec > 127)
        character = "%"+hex.substr(i,2);

    str += character;

}

return decodeURI(str);

    }

Upvotes: 0

Jim Deville
Jim Deville

Reputation: 10672

charCodeAt will get you the decimal value of the string:

"α".charCodeAt(0); //returns 945
0x03b1 === 945; //returns true

toString will then get the hex string

(945).toString(16); // returns "3b1"

(Confirmed to work in IE9 and Chrome)

Upvotes: 23

aroth
aroth

Reputation: 54846

Using mostly plain JavaScript, you should be able to do:

function entityForSymbolInContainer(selector) {
    var code = $(selector).text().charCodeAt(0);
    var codeHex = code.toString(16).toUpperCase();
    while (codeHex.length < 4) {
        codeHex = "0" + codeHex;
    }

    return "&#x" + codeHex + ";";
}

Here's an example: http://jsfiddle.net/btWur/

Upvotes: 31

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