Edit in JSFiddle

$(document).ready(function () {
    var list_elems_jq = $('li').toArray();
    //   var list_elems_pure = toArray('li');
    for (i in list_elems_jq) {
        if (list_elems_jq[i].innerHTML.match(/^php/i)) {
            list_elems_jq[i].style.backgroundColor = "#FF0";
        }
    }
});

<h2>Highlight all list items start with string PHP</h2>

<ul>
    <li>JavaScript</li>
    <li>PHP</li>
    <li>ASP and PHP</li>
    <li>PHP and Perl</li>
    <li>Python</li>
</ul>