Specifically regarding "Can I rely completely upon jquery html() method that it'll perform like innerHTML" my answer is NO!
Run this in internet explorer 7 or 8 and you'll see.
jQuery produces bad HTML when setting HTML containing a <FORM> tag nested within a <P> tag where the beginning of the string is a newline!
There are several test cases here and the comments when run should be self explanatory enough. This is quite obscure, but not understanding what's going on is a little disconcerting. I'm going to file a bug report.
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script>
$(function() {
// the following two blocks of HTML are identical except the P tag is outside the form in the first case
var html1 = "<p><form id='form1'><input type='text' name='field1' value='111' /><div class='foo' /><input type='text' name='field2' value='222' /></form></p>";
var html2 = "<form id='form1'><p><input type='text' name='field1' value='111' /><div class='foo' /><input type='text' name='field2' value='222' /></p></form>";
// <FORM> tag nested within <P>
RunTest("<FORM> tag nested within <P> tag", html1); // succeeds in Internet Explorer
RunTest("<FORM> tag nested within <P> tag with leading newline", "\n" + html1); // fails with added new line in Internet Explorer
// <P> tag nested within <HTML>
RunTest("<P> tag nested within <FORM> tag", html2); // succeeds in Internet Explorer
RunTest("<P> tag nested within <FORM> tag with leading newline", "\n" + html2); // succeeds in Internet Explorer even with \n
});
function RunTest(testName, html) {
// run with jQuery
$("#placeholder").html(html);
var jqueryDOM = $('#placeholder').html();
var jqueryFormSerialize = $("#placeholder form").serialize();
// run with innerHTML
$("#placeholder")[0].innerHTML = html;
var innerHTMLDOM = $('#placeholder').html();
var innerHTMLFormSerialize = $("#placeholder form").serialize();
var expectedSerializedValue = "field1=111&field2=222";
alert( 'TEST NAME: ' + testName + '\n\n' +
'The HTML :\n"' + html + '"\n\n' +
'looks like this in the DOM when assigned with jQuery.html() :\n"' + jqueryDOM + '"\n\n' +
'and looks like this in the DOM when assigned with innerHTML :\n"' + innerHTMLDOM + '"\n\n' +
'We expect the form to serialize with jQuery.serialize() to be "' + expectedSerializedValue + '"\n\n' +
'When using jQuery to initially set the DOM the serialized value is :\n"' + jqueryFormSerialize + '\n' +
'When using innerHTML to initially set the DOM the serialized value is :\n"' + innerHTMLFormSerialize + '\n\n' +
'jQuery test : ' + (jqueryFormSerialize == expectedSerializedValue ? "SUCCEEDED" : "FAILED") + '\n' +
'InnerHTML test : ' + (innerHTMLFormSerialize == expectedSerializedValue ? "SUCCEEDED" : "FAILED")
);
}
</script>
</head>
<div id="placeholder">
This is #placeholder text will
</div>
</html>
