通过ajax更新并获取元素值

<div id="colourSelector" class="row">
<input id="backgroundcolor" name="backgroundcolor" size="6" maxlength="6" type="color" style="display: block;">

</div>

<div id="lineHeight" class="row">
<select name="lineHeight" id="lineHeightSelect">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
</select>
</div>

<div id="divlineDemo" class="section row">
<hr id="lineDemo" style="<?=$model->css_style?>" />

</div>

<script type="text/javascript">

$(function() {
var colorPicker = $('#backgroundcolor');
var headline = $('#lineDemo');
var lineHeight = $('#lineHeightSelect');

lineHeight.on("change", function(){
    headline.css("height", $(this).val() + "px");
});

colorPicker.on("change", function() {
    headline.css('backgroundColor', $(this).val());
});

});


</script>
<div id="colourSelector" class="row">
<input id