javascript - Limit total entries displayed by datalist

Question

When there is a long set of elements in a datalist, they will all get displayed with a scroll bar next to them. Is there an easy way to only display the top 5, and just cut the others off?

For example: http://jsfiddle.net/yxafa/

<input type="text" name="search" id="search" placeholder="type 'r'" list="searchresults" autocomplete="off">
<datalist id="searchresults">
    <option>Ray0</option>
    <option>Ray1</option>
    <option>Ray2</option>
    <option>Ray3</option>
    <option>Ray01</option>
    <option>Ray11</option>
    <option>Ray21</option>
    <option>Ray31</option>
    <option>Ray02</option>
    <option>Ray12</option>
    <option>Ray22</option>
    <option>Ray32</option>
    <option>Ray012</option>
    <option>Ray112</option>
    <option>Ray212</option>
    <option>Ray312</option>
    <option>Ray03</option>
    <option>Ray13</option>
    <option>Ray23</option>
    <option>Ray33</option>
    <option>Ray013</option>
    <option>Ray113</option>
    <option>Ray213</option>
    <option>Ray313</option>
    <option>Ray023</option>
    <option>Ray123</option>
    <option>Ray223</option>
    <option>Ray323</option>
    <option>Ray0123</option>
    <option>Ray1123</option>
    <option>Ray2123</option>
    <option>Ray3123</option>
</datalist>

Answer 1

With some modern javascript and html you could do something like this.

Here's the document:

<template id="resultstemplate">
    <option>Ray0</option>
    <option>Ray1</option>
    <option>Ray2</option>
    <option>Ray3</option>
    <option>Ray01</option>
    <option>Ray11</option>
    <option>Ray21</option>
    <option>Ray31</option>
    <option>Ray02</option>
    <option>Ray12</option>
    <option>Ray22</option>
    <option>Ray32</option>
    <option>Ray012</option>
    <option>Ray112</option>
    <option>Ray212</option>
    <option>Ray312</option>
    <option>Ray03</option>
    <option>Ray13</option>
    <option>Ray23</option>
    <option>Ray33</option>
    <option>Ray013</option>
    <option>Ray113</option>
    <option>Ray213</option>
    <option>Ray313</option>
    <option>Ray023</option>
    <option>Ray123</option>
    <option>Ray223</option>
    <option>Ray323</option>
    <option>Ray0123</option>
    <option>Ray1123</option>
    <option>Ray2123</option>
    <option>Ray3123</option>
</template>
<input type="text" name="search" id="search"  placeholder="type 'r'" list="searchresults" autocomplete="off" />
<datalist id="searchresults"></datalist>

And here's the js:

var search = document.querySelector('#search');
var results = document.querySelector('#searchresults');
var templateContent = document.querySelector('#resultstemplate').content;
search.addEventListener('keyup', function handler(event) {
    while (results.children.length) results.removeChild(results.firstChild);
    var inputVal = new RegExp(search.value.trim(), 'i');
    var clonedOptions = templateContent.cloneNode(true);
    var set = Array.prototype.reduce.call(clonedOptions.children, function searchFilter(frag, el) {
        if (inputVal.test(el.textContent) && frag.children.length < 5) frag.appendChild(el);
        return frag;
    }, document.createDocumentFragment());
    results.appendChild(set);
});

And here's a live example: http://jsfiddle.net/gildean/yxafa/6/