Resizing SVG rect elements inside G tag

Question

I'm using a SVG in a website but I am having some trouble resizing it. It is displayed inside the website's header and, before I implemented the SVG (was using a normal image), I was resizing the image like this:

$("#block_175 img").height($("#header").height() / 2);

Now, since I am using the SVG, I tried several ways of resizing it but I can't seem to find how to do it. Here is how I built the SVG:

<div id='block_175' class=''>
<svg width="100" height="100">
    <g id="cross_svg">
        <rect id="Rectangle-1"  x="0" y="0" width="48" height="2" fill="transparent"></rect>
        <rect id="Rectangle-2"  x="0" y="14" width="48" height="2" fill="transparent"></rect>
        <rect id="Rectangle-4"  x="0" y="28" width="48" height="2" fill="transparent"></rect>
    </g>    
</svg> 

CSS:

svg 
{
    width: 52px;
    height: 52px;
    z-index: 99999;
    transition: all .3s ease;
    cursor: pointer;
}

svg g 
{
    transition: all .3s ease;
    width: 100px;
    height: 100px;
    display: block;
    position: absolute;
    left: 50%;
    top: 50%;
    margin: auto;
    cursor: pointer;
}

svg rect 
{
    transition: all .3s ease;
    fill: #ffffff;
}

svg g 
{
    width: 100px;
    height: 100px;
}

JS:

svg.on('click', function()
        {
            if (i) 
            {
                setTimeout(function()
                {
                    $(this).find("g").addClass('gotcha');

                    line_first.css(
                    {
                        'transform':'rotate(45deg)',
                        'left':'50%',
                        'top':'50%',
                        'width':'200px',
                        // This line BELONGS to @dervondenbergen :D 
                        // Enjoy your propriety my friend.
                        'transform-origin': 'left bottom'
                    })
                    line_third.css(
                    {
                        'transform':'rotate(-45deg) translate(-50%,-50%)',
                        'left':'50%',
                        'top':'50%'
                    })
                    line_second.css('opacity','0')
                },005)
            } 
            else 
            {
                setTimeout(function()
                {
                    line_first.attr('style', '');
                    line_third.attr('style', '');
                    line_second.css('opacity','1')
                },005)
            }

            i =! i; 

            $("#mobile_menu").slideToggle();
        });

So, resuming: I need the SVG to have half the height of #header but I can't find out how to resize the whole SVG.

Thanks.

EDIT 1: (thank you, Pavel Gatnar)

Changed the CSS to this

    svg 
{

        width: 100%;
        height: 100%;
        z-index: 99999;
        transition: all .3s ease;
        cursor: pointer;
    }

    svg g 
    {
        transition: all .3s ease;
        width: 100%;
        height: 100%;
        display: block;
        position: absolute;
        left: 50%;
        top: 50%;
        margin: auto;
        cursor: pointer;
    }

    svg rect 
    {
        transition: all .3s ease;
        fill: #ffffff;
    }

and I'm now resizing the container div instead of the SVG itself, but it doesn't work either. The G element keeps overflowing out of the container div...

Solution

You're missing the 'viewbox' attribute which you should set as:

 <svg width='100' height='100' viewBox='0 0 100 100'>...</svg>

This way you can treat your SVG as an image, and resize it as such.

Without a viewbox, your SVG will not be scaled down when you alter the width and the height.

Here's a comparison of how a SVG with the viewbox and one without the viewbox behave: http://jsfiddle.net/k14qd88j/

Comments

[Faquir]

Editted the first post based on your answer.

[Faquir]

I figgured it out... Editted the first post.

[Faquir]

Oh, you're right! With this I am closer to what I want, thanks a lot!