Question

I am trying to write some Javascript to hide some elements that contain only carriage returns. I appreciate that the correct way to solve this problem would be to stop these elements being created, but unfortunately that is not possible in this instance. I am trying to user a regular expression to search for the unwanted elements but am not having much luck. The function I have written is as follows:

function HideEmptyP()
{

    var patt = (\\r)
    for(var i = 0;i<desc[i].length;i++);
    {
    var desc[i] = document.getElementsByClassName('sitspagedesc');
    var result[i] = patt.test(desc[i]);
        if (result[i] == true)
            {
            desc[i].style.display='none';
            }
        else
            {
            alert("No Match!");
            }
    }

The error I’m getting in the Web Console is ‘Syntax Error: Illegal Character’.

Grateful for any ideas on how to solve this.

Thanks in advance.

Answer 1

I am trying to write some Javascript to hide some elements that contain only carriage returns.

There’s no need for a regular expression for that, just compare the element’s innerHTML property to "\\r", e.g.:

if (demo[i].innerHTML === "\\r") {
    // Remove it
}

But beware that some browsers may transform a single carriage return. You might want to check for "\\r", "\\n", and just a space. To do that, you might want to use a regular expression.

Your regular expression literal ((\\r)) is just completely invalid, it’s worth reading up on them to learn the correct syntax. To write a regular expression literal in JavaScript, you use / as the delimiter. So: /\\r/. To test that a string contains only \r, \n, or space, you can use /^[\r\n ]+$/ (which requires there be at least one character that matches, and uses ^ to indicate start-of-string, and $ to indicate end-of-string):

if (demo[i].innerHTML.match(/^[\r\n ]+$/) {
    // Remove it
}