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This post is transferred from my old Hexo blog site, created on 2014. This blog will be updating continually.

If you want to find specific topic, feel free to use ctrl + F to search for keyword.

Change Glyphicon when Bootstrap Collapse Show or Hide

This is what I learned from: . The answer is from zessx.

<div class="panel-heading" role="tab">
    <a class="collapsed" data-toggle="collapse" data-parent="#accordion" href="#test" aria-expanede="true" aria-controls="test">
        <span class="glyphicon glyphicon-plus"></span>
        Here, when a panel is collapsed, a glyphicon-plus will appear.
        When it is toggled (i.e, change to a different state, which is not collapsed), a glyphicon-minus will appear.

<script type="text/javascript">
    function toggleChevron(e) {
        .find('span') //find elements that has tage 'span'
        .toggleClass('glyphicon glyphicon-minus glyphicon-plus');
    $('#accordion').on('', toggleChevron);
    $('#accordion').on('', toggleChevron);

Collapse Panel Hide or Show

hide: will hide panel

show: will show panel

toggle: will change to opposite status

To use this, try $('.class_name').collapse('toggle'); or $('#id_name').collapse('hide').

Sticky Header/Footer

Bootstrap has two classes: navbar-fixed-top and navbar-fixed-bottom that can be served as sticky header and footer. Make sure add body{ padding-top: 50px;} or body{ padding-bottom: 50px;} when you use them.

Note: the default height for navbar in Bootstrap3 is 50px high.

Dynamically Edit Checkbox

Default Status

In Bootstrap3, when you add a simple check box, the default code is <input type="checkbox" />.

This checkbox will keep un-checked. When you check it, this default code will keep the same.

If you use this.getAttribute('checked') to check if checkbox is checked or not, you always get undefined.

Default Checked Status

In Bootstrap3, you can set a default checked attribute to checkbox to make it default checked: <input type='checkbox' checked/>.

If you use $(this).attr('checked') to check status, it will return checked or undefined. But if you use this.getAttribute("checked"), you will always get empty value returned.

If you use <input type='checkbox' checked = "checked"/>, $(this).attr('checked') will return same result as above, but this.getAttribute("checked") will always get checked no matter if you check it or not.

You can also set <input type='checkbox' checked="checked"/> to make it default checked.

Change Status

Following JQuery Code can divide status of checkbox if someone check or uncheck it:

    //You should change 'type=checkbox' based on your code. 'name' can be skipped
        if($(this).attr('checked') == undefined){
            $(this).attr("checked", "checked");
            //steps for a checked checkbox...
            //steps for an un-checked checkbox...

The usage of code above: when you check the checkbox, this default code will become <input type='checkbox' checked='checked'>. If you un-check it, code will change back to <input type="checkbox" />.

In this case, if you use $(this).attr(checked) or this.getAttribute(checked) to check the status of checkbox, the un-checked checkbox will return undefined. the checked checkbox will return checked.

Check/UnCheck Checkbox Using JavaScirpt

In Bootstrap3, you can also set the checked attribute of checkbox to true or false.

If you use JQuery, $(this).attr("checked",false) will remove checked attribute in code.

If you use pure JavaScript, You have two steps to do this:

  • this.setAttribute("checked", true) or this.setAttribute("checked", "checked") can change the code but not behavior. i.e. code will become <input type='checkbox' checked='checked'> or <input type='checkbox' checked='true'>, but on user interface, checkbox is not checked

  • this.checked="checked" or this.checked = true will only change use interface. Your checkbox will be checked buy there is nothing changed in code.

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