How to Check if a Div is Empty and Then Execute Action

问题

I'm Building a Personal Assistant with HTML5, CSS, & Javascript

This is what my current Problem is.

I Have a <div> that contains scripts with the responses for when a Question is asked and if the question matches one it writes that response.

I Need a Script that will check if this div is empty, in Javascript, not jQuery

I need to check if the div is empty because that means there is no response.

Then for it to redirect to an the error page.

a Question & the response to it would look like this:

    <script type="text/javascript">
{
var q = getValue("q");
var name = getValue("name");
}
if (q == 'Whats+up') {
document.write("Not much " + name + ".");
}
else {

}
</script>

This is the last code I tried:

            <script>

    var theDiv = document.getElementById("responce");
    var q = getValue("q");
    if(theDiv.innerHTML == ''){
    window.location = 'error.html?name=Brandon&q='+q;
    }
  </script>

回答1:

Try this

<script type="text/javascript">
{
var q = getValue("q");
var name = getValue("name");
}
if (q == 'Whats+up') {
document.write("<div id='response_text'>"+"Not much " + name + "."+"</div>");
}
else {

}
</script>

And then:

<script>

var theDiv = document.getElementById("response_text");
var q = getValue("q");
if(theDiv==null || theDiv.innerHTML == ''){
window.location = 'error.html?name=Brandon&q='+q;
}
</script>

That being said, there are probably better/more scalable ways of doing this with ajax.

回答2:

You could check, if there are no other elements than scripts in the div:

<script>
    var theDiv = document.getElementById('responce'),
        q = getValue('q'),
        scripts = theDiv.getElementsByTagName('SCRIPT').length;
    if (theDiv.children.length - scripts === 0) {
        window.location = 'error.html?name=Brandon&q=' + q;
    }
</script>

However, I'd suggested you to get rid of all inline scripts, and put them in the head of the document or just before the closing body tag instead.

EDIT

A quick-fix would be to move the script below the #responce.

来源：https://stackoverflow.com/questions/12863884/how-to-check-if-a-div-is-empty-and-then-execute-action

标签

javascript

html

redirect

contains