jQuery.browser.mobile is forgotten at document ready

StackOverflow https://stackoverflow.com/questions/17869513

Question

I'm trying to use the jQuery.browser.mobile plugin found on detectmobilebrowsers.com. I included jQuery and copied the provided snippet into the <head> of my ASP page, above another <script> doing other things:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
    /**
     * jQuery.browser.mobile (http://detectmobilebrowser.com/)
     *
     * jQuery.browser.mobile will be true if the browser is a mobile device
     *
     **/
    (function(a){(jQuery.browser=jQuery.browser||{}).mobile=/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(a.substr(0,4))})(navigator.userAgent||navigator.vendor||window.opera);
</script>

But at the document ready event, jQuery.browser.mobile is being forgotten. If I reduce my document ready code to this: 

$(document).ready(function() {
    alert("at document.ready: jQuery.browser.mobile === " + jQuery.browser.mobile);
});

That alerts "at document.ready: jQuery.browser.mobile === undefined". Yet its <script> tag is after the tag for the jQuery.browser.mobile plugin, so it should have loaded already.

If I this put in another <script> element right after my plugin-loading <script>:

alert("in script tag: jQuery.browser.mobile === " + jQuery.browser.mobile);

That alerts "in script tag: jQuery.browser.mobile === false".

Why is jQuery.browser.mobile being forgotten?

Was it helpful?

Solution

In my case, the problem was that I was unknowingly loading jQuery twice. When jQuery loads, it appears that it creates a new jQuery object from scratch, which has the effect of deleting all custom properties already set on the jQuery object.

To find the source of the problem, I moved this code around the page until I found the first line after which it started saying jQuery.browser.mobile was undefined:

<script>
    alert("in script tag in middle: jQuery.browser.mobile === " + jQuery.browser.mobile);
</script>

The line was this:

<!--#include file="include/set_hm.inc"-->

That line included a file that contained this line, loading jQuery:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>

If I delete that line, then jQuery.browser.mobile keeps its value as it should.

To fix my problem with jQuery.browser.mobile, I just need to make sure the plugin is loaded after jQuery. I could do this by extracting the jQuery inclusion from that included file, or by moving the plugin loading to after the file inclusion.

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