使用纯JavaScript禁用基于innerhtml的选择选项

Question

Scenario: User votes via HTML form for a field trip to take on a bus. There are three options:

    <select id="selectbox">
      <option>Berlin</option>
      <option>Munich</option>
      <option>Cologne</option>
    </select>

The free bus seats are stored in / read from a database: ($tour is our array keeping the free seats)

<table class="status">
  <tr><td>Berlin: <span id="t1">available (<?php echo $tour[0]; ?> seats)</span></td></tr>
  <tr><td>Munich: <span id="t2">available (<?php echo $tour[1]; ?> seats)</span></td></tr>
  <tr><td>Cologne: <span id="t3">available (<?php echo $tour[2]; ?> seats)</span></td></tr>
</table>

If free seats are zero, we display a "sorry, booked out" info using vanilla JavaScript:

// get content of status table
var t1 = document.getElementById("t1").innerHTML;
var t2 = document.getElementById("t2").innerHTML;
var t3 = document.getElementById("t3").innerHTML;
var bookedout = "sorry, booked out!"

    // check if condition is met
if (t1 == "available (0 seats)") {
    document.getElementById("t1").innerHTML = bookedout;
}
if (t2 == "available (0 seats)") {
    document.getElementById("t2").innerHTML = bookedout ;
}
if (t3 == "available (0 seats)") {
    document.getElementById("t3").innerHTML = bookedout ;
}

Works fine. However, now comes the part I'm a bit lost. The above condition should also delete the respective option from #selectbox based on the option's innerHTML . In jQuery I'd go with something like #selectbox option:contains('stringhere').

However, I wanna do it in the purest of JavaScript. Any ideas?

Answer 1

It's fairly straight forward..

First in your html give vlaues to your options:

<select id="selectbox">
  <option>Berlin</option>
  <option>Munich</option>
  <option>Cologne</option>
</select>

Then in js:

var mySelect = document.getElementById("selectbox");
//function to get option values as array
function getOptionsArr() {
var optionsArray =[],options = mySelect.options; 
var i = 0, len = options.length;
// store the options value in an array
while (i < len)
{
  optionsArray.push(options[i++].value);
}
    return optionsArray;
}
var t1 = document.getElementById("t1").innerHTML;
var t2 = document.getElementById("t2").innerHTML;
var t3 = document.getElementById("t3").innerHTML;
var bookedout = "sorry, booked out!"

// check if condition is met
if (t1 == "available (0 seats)"){
    document.getElementById("t1").innerHTML = bookedout;
    //this will get the whole parent node and child node inner text we split at : and get the value
    var textArr = document.getElementById("t1").parentElement.innerText.split(':');
 // find the index of value from our array created above and remove that option from select
 mySelect.remove(getOptionsArr().indexOf(textArr [0]))
}
//repeat the same for other
if (t2 == "available (0 seats)"){
 document.getElementById("t2").innerHTML = bookedout ;
 var textArr = document.getElementById("t2").parentElement.innerText.split(':');
 mySelect.remove(getOptionsArr().indexOf(textArr [0]))
}
if (t3 == "available (0 seats)"){
document.getElementById("t3").innerHTML = bookedout ;
 var textArr = document.getElementById("t3").parentElement.innerText.split(':');
 mySelect.remove(getOptionsArr().indexOf(textArr [0]))
}

Aditionally you can refactor it by

var mySelect = document.getElementById("selectbox");
//function to get option values as array
function getOptionsArr() {
var optionsArray =[],options = mySelect.options; 
var i = 0, len = options.length;
// store the options value in an array
while (i < len)
{
  optionsArray.push(options[i++].value);
}
    return optionsArray;
}

var t1 = document.getElementById("t1").innerHTML;
var t2 = document.getElementById("t2").innerHTML;
var t3 = document.getElementById("t3").innerHTML;
var bookedout = "sorry, booked out!"

// check if condition is met
if (t1 == "available (0 seats)"){
    doUpdateDOM("t1")
}
if (t2 == "available (0 seats)"){
doUpdateDOM("t2")
}
if (t3 == "available (0 seats)"){
doUpdateDOM("t3")
}

function doUpdateDOM(nodeID){
    document.getElementById(nodeID).innerHTML = bookedout;
    var textArr = document.getElementById(nodeID).parentElement.innerText.split(':');
 mySelect.remove(optionsArray.indexOf(textArr [0]))
}

Answer 2

Assuming that the order of the options inside the select correspond to the order inside the table element you could simply do something like this.

 var select = document.getElementById('selectbox'); var table = document.getElementsByClassName('status').item(0); var rows = table.rows; var bookedout = " sorry, booked out!"; // check whether an option is bookedout // and save its state to a new array. var bookedOutState = [].slice.call(rows).map(function(row) { var match = row.children[0].textContent.match(/\\d/); if (+match[0] === 0) { row.children[0].textContent = match['input'].substr(0, match['input'].indexOf(':') + 1) + bookedout; return false; } return true; }) // go over the new created array and remove // options from select according to the saved state. bookedOutState.forEach(function(state, idx) { if (!state) { select.removeChild(select.children[idx]) } }) 

 <select id="selectbox"> <option>Berlin</option> <option>Munich</option> <option>Cologne</option> </select> <table class="status"> <tr><td>Berlin: <span id="t1">available 0 seats</span></td></tr> <tr><td>Munich: <span id="t2">available 1 seats</span></td></tr> <tr><td>Cologne: <span id="t3">available 2 seats</span></td></tr> </table>