Regex if certain string is included between particular HTML tags

Question

I have the below html as a text string

<p>I'll write a H1 below</p>
<h1>Hi I'm H1</h1>
<p>Last p</p>

What i want to do is see if 'I'm H1' exists in the h1 tag - curious as to what the regex above would be so that it returns true

P.S: Even if it contained <h1>I'm H1 buddy</h1> it should return true so essentially in a h1 tag, if it contains a particular string, in the above case 'I'm H1', it should output true

If it is the plain regex you want, then here it is, \<h1\>.(I'm H1).\</h1\>. It will work if the whole thing is a string. — Vinod Kumar
– Vinod Kumar, Commented Jun 1, 2015 at 13:22
@VinodKumar Did you try that? Doesn't work for the example provided (there's no character after the "I'm H1" to match the . and only matches one character before. Could be SO removing '*' ? — fdomn-m
– fdomn-m, Commented Jun 1, 2015 at 13:25
I am sorry, my mistake. I did not try. This should work \<h1\>.*?(I'm H1).*?\<\/h1\> — Vinod Kumar
– Vinod Kumar, Commented Jun 1, 2015 at 13:28
Not sure why this was tagged with javascript, but that's why you're getting javascript answers... — fdomn-m
– fdomn-m, Commented Jun 1, 2015 at 13:30

Bill the Lizard · Accepted Answer · 2015-06-01 13:33:25Z

1

The following regex should work:

<h1>.*I'm H1.*<\/h1>

That's <h1> followed by optional text (.*), followed by "I'm H1", followed by more optional text (.*), followed by </h1>.

Demonstration on Online regex tester.

edited Jun 1, 2015 at 13:33

answered Jun 1, 2015 at 13:25

Bill the Lizard

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2 Comments

user3721307 Over a year ago

thanks, this is the simplest way to do it and it just works - one question regarding escaping - the keyword i'm trying to test with is a variable - say 'var keyword' with a particular value and the following does not work: new RegExp("/<h1>.*?" + "http redirect 302" + ".*?<\/h1>/gi").test(plainHtml)

user3721307 Over a year ago

pretty sure i'm not escaping it properly but don't know what the right way to do it is

emartinelli · Accepted Answer · 2015-06-01 13:34:38Z

1

It is a way to solve your problem with Regex.

var re = /<h1>.*?\sI'm\sH1.*?<\/h1>/; 
var str = '<p>I\'ll write a H1 below</p>\n<h1>Hi I\'m H1 buddy</h1>\n<p>Last p</p>';
var m;
 
if ((m = re.exec(str)) !== null) {
    if (m.index === re.lastIndex) {
        re.lastIndex++;
    }
    // View your result using the m-variable.
    // eg m[0] etc.
}

document.getElementById("results").innerHTML = m != null

<div id="results"></div>

edited Jun 1, 2015 at 13:34

answered Jun 1, 2015 at 13:29

emartinelli

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1 Comment

Radonirina Maminiaina Over a year ago

And what happen if the OP add buggy?

Radonirina Maminiaina · Accepted Answer · 2015-06-01 13:25:06Z

0

You can try this:

/(I'm H1)/.test("Hi I'm H1") // return true
/(I'm H1)/.test("Hi I'm H1 buddy") // return true

answered Jun 1, 2015 at 13:25

Radonirina Maminiaina

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Comments

fdomn-m · Accepted Answer · 2015-06-01 13:26:52Z

0

<h1>.*?I'm\sH1.*?</h1>

.*? any or none characters with minimum match (so doesn't match multiple H1s)
\s for any whitespace
I'm\sH1 literal

Edit: no need to escape < and >

edited Jun 1, 2015 at 13:26

answered Jun 1, 2015 at 13:24

fdomn-m

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Comments

mplungjan · Accepted Answer · 2015-06-01 13:51:09Z

-1

Is there a reason you need a regex?

if (document.getElementsByTagName('h1')[0].innerHTML.indexOf("Hi I'm H1") != -1) 
{ 

}

edited Jun 1, 2015 at 13:51

mplungjan

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answered Jun 1, 2015 at 13:22

Squiggs.

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