Edit in JSFiddle

$('button.one').text('Select Images');
$('button.two').html('Select <span>Images</span>');
$('button.three').attr('style','color:blue');
<p>The text on the button below should be "Upload Images" as coded on HTML but with the help of jQuery, it is changed to "Select Images"</p>
<button class="one">Upload Images</button>

<p>You may want to change a value with HTML too. On the button below, I added span. This is just one of many possibilities</p>
<button class="two">Submit</button>

<p>You can also change values from attributes like class, id, style etc. The following button's style attribute will be changed</p>
<button class="three" style="color:green">Cool Button</button>

<p>Please check HTML tab to review the changes</p>