regex for changing height and width value in an embed code

Question

HI

I have an application where users can paste their embed code.While displaying I want to change the height and width of the embed code to a fixed value of my choice. Can you tell me the regular expression to find the width and height in the embed code. width="300" height="500". I want to be able to get these two values completely so that I can replace them.

Thanks

Answer 1

This one does it:

width="(.*?)" height="(.*?)"

and grab the first and second values. What language are you using? The implementation might be different.

In PHP:

     $pattern = '/width="(.*?)" height="(.*?)"/';
     $subject = 'width="500" height="300"';

     preg_match($pattern, $subject, $matches);

     print_r($matches);

Answer 2

The following examples take into account the ordering, what quotations are used, and if people put in spaces

A straight replace:

embeddedString = embeddedString.replace(/(width\s*=\s*["'])[0-9]+(["'])/ig, $1 + yourWidth + $2);
embeddedString = embeddedString.replace(/(height\s*=\s*["'])[0-9]+(["'])/ig, $1 + yourHeight + $2);

Or to transform the width:

embeddedString = embeddedString.replace(/width\s*=\s*["']["']/ig, function($0, $1)
{
    return $1 * 2;
});

if you actually want to remove the whole thing, but use the values:

var originalWidth;
var originalHeight;
embeddedString = embeddedString.replace(/(?:width|height)\s*=\s*["']([0-9]+)["']\s*(?:width|height)\s*=\s*["']([0-9]+)["']/ig, function($0, $1, $2, $3, $4)
{
    // $0 = original string
    // $1 = either 'width' or 'height'
    // $2 = the value of width or height, depending on above
    // $3 = either 'width' or 'height'
    // $4 = the value of width or height, depending on above
    // here you might want to set another value, eg:
    originalWidth = $2;
    return "";
});

Answer 3

Regexes are fundamentally bad at parsing HTML (see Can you provide some examples of why it is hard to parse XML and HTML with a regex? for why). What you need is an HTML parser. See Can you provide an example of parsing HTML with your favorite parser? for examples using a variety of parsers.

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