jQuery UI: Set slider scrollbar's position

Question

I'm using jQuery UI's slider scrollbar and I would like to position it when the page loads. I'm using the sample code from example, but I've never worked with jQuery UI before, so I don't know what I need to change. The position of slider should be under some value (in example are 20 values) and the value should be visible.

How to do that?

Answer 1

Simply specify the value when you initialise the slider:

HTML:

<div id="slider"></div>

Javascript:

$(function() 
{
    $( "#slider" ).slider(
    {
        min : 0,
        max: 10,
        value : 5 
    });
});

Fiddle

Update

JS:

$(function() 
{
    //scrollpane parts
    var scrollPane = $( ".scroll-pane" ),
    scrollContent = $( ".scroll-content" );

    //build slider
    var initialValue = 75; // 0 - 99 

    var scrollbar = $( ".scroll-bar" ).slider(
    {
        value : initialValue,
        slide: function( event, ui ) 
        {
            if ( scrollContent.width() > scrollPane.width() ) 
            {
                scrollContent.css( "margin-left", Math.round(
                    ui.value / 100 * ( scrollPane.width() - scrollContent.width() )
                ) + "px" );
            } 
            else 
            {
                scrollContent.css( "margin-left", 0 );
            }
        }
    });

    // Update offset position based on initialValue
    scrollContent.css( "margin-left", Math.round(
        initialValue / 100 * ( scrollPane.width() - scrollContent.width() )
    ) + "px" );

    //append icon to handle
    var handleHelper = scrollbar.find( ".ui-slider-handle" )
        .mousedown(function() 
        {
            scrollbar.width( handleHelper.width() );
        })
        .mouseup(function() 
        {
            scrollbar.width( "100%" );
        })
        .append( "<span class='ui-icon ui-icon-grip-dotted-vertical'></span>" )
        .wrap( "<div class='ui-handle-helper-parent'></div>" ).parent();

    //change overflow to hidden now that slider handles the scrolling
    scrollPane.css( "overflow", "hidden" );

    //size scrollbar and handle proportionally to scroll distance
    function sizeScrollbar() 
    {
        var remainder = scrollContent.width() - scrollPane.width();
        var proportion = remainder / scrollContent.width();
        var handleSize = scrollPane.width() - ( proportion * scrollPane.width() );
        scrollbar.find( ".ui-slider-handle" ).css(
        {
            width: handleSize,
            "margin-left": -handleSize / 2
        });
        handleHelper.width( "" ).width( scrollbar.width() - handleSize );
    }

    //reset slider value based on scroll content position
    function resetValue() 
    {
        var remainder = scrollPane.width() - scrollContent.width();
        var leftVal = scrollContent.css( "margin-left" ) === "auto" ? 0 :
            parseInt( scrollContent.css( "margin-left" ) );
        var percentage = Math.round( leftVal / remainder * 100 );
        scrollbar.slider( "value", percentage );
    }

    //if the slider is 100% and window gets larger, reveal content
    function reflowContent() 
    {
        var showing = scrollContent.width() + parseInt( scrollContent.css( "margin-left" ), 10 );
        var gap = scrollPane.width() - showing;
        if ( gap > 0 ) 
        {
            scrollContent.css( "margin-left", parseInt( scrollContent.css( "margin-left" ), 10 ) + gap );
        }
    }

    //change handle position on window resize
    $( window ).resize(function() 
    {
        resetValue();
        sizeScrollbar();
        reflowContent();
    });
    //init scrollbar size
    setTimeout( sizeScrollbar, 10 );//safari wants a timeout
});

CSS:

.scroll-pane { overflow: auto; width: 99%; float:left; }
.scroll-content { width: 2440px; float: left; }
.scroll-content-item { width: 100px; height: 100px; float: left; margin: 10px; font-size: 3em; line-height: 96px; text-align: center; }
.scroll-bar-wrap { clear: left; padding: 0 4px 0 2px; margin: 0 -1px -1px -1px; }
.scroll-bar-wrap .ui-slider { background: none; border:0; height: 2em; margin: 0 auto;  }
.scroll-bar-wrap .ui-handle-helper-parent { position: relative; width: 100%; height: 100%; margin: 0 auto; }
.scroll-bar-wrap .ui-slider-handle { top:.2em; height: 1.5em; }
.scroll-bar-wrap .ui-slider-handle .ui-icon { margin: -8px auto 0; position: relative; top: 50%; }

HTML:

<div class="scroll-pane ui-widget ui-widget-header ui-corner-all">
    <div class="scroll-content">
        <div class="scroll-content-item ui-widget-header">1</div>
        <div class="scroll-content-item ui-widget-header">2</div>
        <div class="scroll-content-item ui-widget-header">3</div>
        <div class="scroll-content-item ui-widget-header">4</div>
        <div class="scroll-content-item ui-widget-header">5</div>
        <div class="scroll-content-item ui-widget-header">6</div>
        <div class="scroll-content-item ui-widget-header">7</div>
        <div class="scroll-content-item ui-widget-header">8</div>
        <div class="scroll-content-item ui-widget-header">9</div>
        <div class="scroll-content-item ui-widget-header">10</div>
        <div class="scroll-content-item ui-widget-header">11</div>
        <div class="scroll-content-item ui-widget-header">12</div>
        <div class="scroll-content-item ui-widget-header">13</div>
        <div class="scroll-content-item ui-widget-header">14</div>
        <div class="scroll-content-item ui-widget-header">15</div>
        <div class="scroll-content-item ui-widget-header">16</div>
        <div class="scroll-content-item ui-widget-header">17</div>
        <div class="scroll-content-item ui-widget-header">18</div>
        <div class="scroll-content-item ui-widget-header">19</div>
        <div class="scroll-content-item ui-widget-header">20</div>
    </div>
    <div class="scroll-bar-wrap ui-widget-content ui-corner-bottom">
        <div class="scroll-bar"></div>
    </div>
</div>

http://jsfiddle.net/pFwFj/