How to detect IE7 and lower using jQuery.support?

This small function will tell you whether the button code is broken:

function isButtonBroken()
{
    var b = document.createElement('button');

    b.value = 1;
    b.appendChild(document.createTextNode('2'));

    return b.value === '12';
}

jQuery.Support does not give you the browser. As of jQuery 1.9 the $.browser function is deprecated. If your after a quick was the easiest way is to use the browsers native navigator object.

//check for IE7
if(navigator.appVersion.indexOf("MSIE 7.")!=-1)

Using Modernizr

//check for IE7 or less
if ($('html').hasClass('lt-ie7');

This is not recommended however as the browser can easily "spoof" this object. Using a library such as Moderizer to feature detect is modern approach. For more details info see: 5+ WAYS TO CHECK IE VERSION USING JAVASCRIPT/JQUERY

As others have said trying to detect a browser version is a bad idea and you should rely on feature detection.

That said the only reliable way to detect an IE browser rendering engine is using conditional comments. You can use this little snippet that'll get it for you:

var ie = (function(){

    var undef,
        v = 3,
        div = document.createElement('div'),
        all = div.getElementsByTagName('i');

    while (
        div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
        all[0]
    );

    return v > 4 ? v : undef;

}());

Keep in mind that this will only work in IE versions supporting conditional comments and it will not work in IE10 or above.

A no script solution can be based on giving the button a type of submit and a name that is the value you want to submit. Then, at the server, make the action dependent on the value of the name attribute, not the value, e.g.

<button type="submit" name="whatever" value="Click me 0">Click me 0</button>

Now every browser will submit the button as &whatever=Click+me+0. I don't have IE 7 to test with, but from what you've posted, that should work.

If you have multiple buttons in the form, only the one that is clicked to submit the form will be successful, so only that button's name and value will be submitted.

Of course the simplest of all is to use input type submit, but maybe you can't do that.

U Can detect by using following condition.

if (!$.support.leadingWhitespace) {
    //IE7 stuff
}

You cannot detect the browser using jQuery.support.

Rather than checking the browser, you should check the feature of browsers you want to use.

For example, if you want to use ajax feature, you sould check the presence of XMLHttpRequest object by jQuery.support.ajax

var ajaxEnabled = $.support.ajax;
if (ajaxEnabled) {
  // do something
}

jQuery.browser document says that

jQuery.browser may be moved to a plugin in a future release of jQuery.

And also says that

Because $.browser uses navigator.userAgent to determine the platform, it is vulnerable to spoofing by the user or misrepresentation by the browser itself. It is always best to avoid browser-specific code entirely where possible. The $.support property is available for detection of support for particular features rather than relying on $.browser.

You can make your own browser-detection code. See below. But keep in mind that this code is vulnerable to spoofing as jQuery document says.

var ua = navigator.userAgent.toLowerCase();

var isOpera : (ua.indexOf('opera') >= 0) ? true : false;
var isFirefox : (ua.indexOf('firefox') >= 0) ? true : false;
var isMSIE : (ua.indexOf('msie') >= 0) ? true : false;
var isMSIE6 : (ua.indexOf('msie 6.0') >= 0) ? true : false;
var isMSIE7 : (ua.indexOf('msie 7.0') >= 0) ? true : false;
var isMSIE8 : (ua.indexOf('msie 8.0') >= 0) ? true : false;
var isMSIE9 : (ua.indexOf('msie 9.0') >= 0) ? true : false;
// and other browsers...