How to get html tag attribute values using JavaScript Regular Expressions?

Question

Suppose I have this HTML in a string:

<meta http-equiv="Set-Cookie" content="COOKIE1_VALUE_HERE">
<meta http-equiv="Set-Cookie" content="COOKIE2_VALUE_HERE">
<meta http-equiv="Set-Cookie" content="COOKIE3_VALUE_HERE">

And I have this regular expression, to get the values inside the content attributes:

/<meta http-equiv=[\"']?set-cookie[\"']? content=[\"'](.*)[\"'].*>/ig

How do I, in JavaScript, get all three content values?

I've tried:

var setCookieMetaRegExp = /<meta http-equiv=[\"']?set-cookie[\"']? content=[\"'](.*)[\"'].*>/ig;
var match = setCookieMetaRegExp.exec(htmlstring);

but match doesn't contain the values I need. Help?

Note: the regular expression is already correct (see here). I just need to match it to the string. Note: I'm using NodeJS

Answer 1

You were so close! All that needs to be done now is a simple loop:

var htmlString = '<meta http-equiv="Set-Cookie" content="COOKIE1_VALUE_HERE">\n'+
'<meta http-equiv="Set-Cookie" content="COOKIE2_VALUE_HERE">\n'+
'<meta http-equiv="Set-Cookie" content="COOKIE3_VALUE_HERE">\n';

var setCookieMetaRegExp = /<meta http-equiv=[\"']?set-cookie[\"']? content=[\"'](.*)[\"'].*>/ig;

var matches = [];
while (setCookieMetaRegExp.exec(htmlString)) {
  matches.push(RegExp.$1);
}

//contains all cookie values
console.log(matches);

JSBIN: http://jsbin.com/OpepUjeW/1/edit?js,console

Answer 2

Keep it simple:

/content=\"(.*?)\">/gi

demo: http://regex101.com/r/dF9cD8

Update (based on your comment):

/<meta http-equiv=\"Set-Cookie\" content=\"(.*?)\">/gi

runs only on this exact string. Demo: http://regex101.com/r/pT0fC2

You really need the (.*?) with the question mark, or the regex will keep going until the last > it finds (or newline). The ? makes the search stop at the first " (you can change this to [\"'] if you want to match either single or double quote).

Answer 3

no need for regular expressions just do some dom work

var head = document.createElement("head");
head.innerHTML = '<meta http-equiv="Set-Cookie" content="COOKIE1_VALUE_HERE"><meta http-equiv="Set-Cookie" content="COOKIE2_VALUE_HERE"><meta http-equiv="Set-Cookie" content="COOKIE3_VALUE_HERE">';

var metaNodes = head.childNodes;
for(var i=0; i<metaNodes.length; i++){
   var contentValue = metaNodes[i].attributes.getNamedItem("content").value;
}

As you are using nodejs and BlackSheep mentions using cheerio you could use their syntax if you wish to use that lib:

//Assume htmlString contains the html
var cheerio = require('cheerio'),
$ = cheerio.load(htmlString);
var values=[];
$("meta").each(function(i, elem) {
  values[i] = $(this).attr("content");
});

Answer 4

Try this

(?:class|href)([\s='"./]+)([\w-./?=&\\#"]+)((['#\\&?=/".\w\d]+|[\w)('-."\s]+)['"]|)

example :

function getTagAttribute(tag, attribute){    
    var regKey = '(?:' + attribute + ')([\\s=\'"./]+)([\\w-./?=\\#"]+)(([\'#\\&?=/".\\w\\d]+|[\\w)(\'-."\\s]+)[\'"]|)'
    var regExp = new RegExp(regKey,'g');
    var regResult = regExp.exec(tag);   
    if(regResult && regResult.length>0){                        
        var splitKey = '(?:(' + attribute + ')+(|\\s)+([=])+(|\\s|[\'"])+)|(?:([\\s\'"]+)$)'                
        return regResult[0].replace(new RegExp(splitKey,'g'),'');
    }else{
        return '';
    }
}


getTagAttribute('<a href  =   "./test.html#bir/deneme/?k=1&v=1"    class=   "xyz_bir-ahmet abc">','href');'

//return  "./test.html#bir/deneme/?k=1&v=1"

Live Regexp101

Live JS Script Example

Answer 5

try this:

var setCookieMetaRegExp = "/<meta http-equiv=[\"']?set-cookie[\"']? content=[\"'](.*)[\"'].*>/ig";
var match = stringToFindPartFrom.match(setCookieMetaRegExp);

Answer 6

Try this:

var myString = '<meta http-equiv="Set-Cookie" content="COOKIE2_VALUE_HERE">';
var myRegexp = /<meta http-equiv=[\"']?set-cookie[\"']? content=[\"'](.*)[\"'].*>/ig;
var match = myRegexp.exec(myString);
alert(match[1]); // should show you the part