I am trying to use a for loop in html but i dont even know if this is possible. Is it? and if yes how? I dont want to use php. only html and javascript.
this is my goal: i have a file containing .txt files. i want to count the number of txt files and when i get the number i want to send it to where i will use a for loop to put the txt file's numbers in a dropbox.
Thanks
Lots of answers.... here is another approach NOT using document.write OR innerHTML OR jQuery....
HTML
<select id="foo"></select>
JS
(function() { // don't leak
var elm = document.getElementById('foo'), // get the select
df = document.createDocumentFragment(); // create a document fragment to hold the options while we create them
for (var i = 1; i <= 42; i++) { // loop, i like 42.
var option = document.createElement('option'); // create the option element
option.value = i; // set the value property
option.appendChild(document.createTextNode("option #" + i)); // set the textContent in a safe way.
df.appendChild(option); // append the option to the document fragment
}
elm.appendChild(df); // append the document fragment to the DOM. this is the better way rather than setting innerHTML a bunch of times (or even once with a long string)
}());
And here is a Fiddle to demo it.
Yes you can for example write this code in html body tag
<select>
<script language="javascript" type="text/javascript">
for(var d=1;d<=31;d++)
{
document.write("<option>"+d+"</option>");
}
</script>
</select>
HTML is not a programming language, just a markup language, so it doesn't include things like for loops or if statements. Javascript does though. You could use javascript to generate/manipulate the HTML, and thus use for loops to create your <option> tags inside the <select>. As a startup for javascript see checkout w3schools.com
I don't like using plain javascript though, I would rather choose a javascript framework like jQuery to do this. Using jquery it is really easy to do cross-platform compatible manipulation of the HTML dom using javascript. You would only need to include some extra javascript files inside your HTML to get it working. See http://jquery.com/
An example of using jquery would be this:
<select id='myselect'></select>
<script type='text/javascript'>
var values=[[1,'tree'],[2,'flower'],[3,'car']];
for(v in values){
var option=$('<option></option>');
option.attr('value',values[v][0]);
option.text(values[v][1]);
$('#myselect').append(option);
}
</script>
You can also try this out on http://jsfiddle.net/6HUHG/3/
One way is to use DynamicHTML. Let the html page have a place holder for the options of select tag.
<select id="selectBox"></select>
In a js file
var options = ["one","two","three"], selectHtml = "";
for(var optionIndex = 0; optionIndex < options.length; optionIndex++) {
selectHtml += ("<option>" + options[optionIndex] + "</option>");
}
document.getElementById("selectBox").innerHTML = selectHtml;
Put the above code in a function and call that function onload.
No you can't use a for loop in HTML. HTML is a markup language, you cannot use logical code. However you could use javascript to do your logic depending on what your objective is.
Here is an example using jQuery, a popular javascript library:
for(i=0; i<5; i++){
$("select").append("<option>" + i + "</option>");
}
See example: http://jsfiddle.net/T4UXw/
May be you can play with javascript and innerHTML. Try this
HTML
<body onload="selectFunction()">
<select id="selectId">
</select>
Javascript
function selectFunction(){
var x=0;
for(x=0;x<5;x++){
var option = "<option value='" + x + "'>Label " + x + "</option>"
document.getElementById('selectId').innerHTML += option;
}
}
来源：https://stackoverflow.com/questions/12725265/is-it-possible-to-use-a-for-loop-in-select-in-html-and-how