Sometimes you have some information on your page and your visitors might want to copy it. The easiest way is to provide a mechanism that allows them to simply click a button to do so. You have to paste this code into the head of your web page

gistfile1.js

<script language="javascript">
/* Source: http://www.apphp.com/index.php?snippet=php-get-remote-ip-address */
function CopyText(el){

    var selectedText = "";
    if(window.getSelection){

        selectedText = window.getSelection();

    }else if (document.getSelection){

        selectedText = document.getSelection();

    }else if (document.selection){

        selectedText = document.selection.createRange().text;

    } 

    if(selectedText != ""){

        selectedText = selectedText.toString();

        el.focus();
        el.value = selectedText;
        }else {
        alert("Select a text in the page and then press this button!");
    }
}
</script>
Select any part of this text to copy it...
<form name="frmCopyText">
<textarea name="txtSelect" rows="4" cols="45"></textarea><br>
<input onclick="CopyText(this.form.txtSelect)"
       type="button"
       value="Press to copy the highlighted text"
       name="btnCopy">
</form>