My function returns a string but comparison is always wrong

Question

I have a PHP function which returns true or false as a String (this works). If I look into my JS file I make an alert box with the responseText of the XMLHttprequest (this works as well). But as soon as I try to compare the responsestring to another string the outcome is always false.

I've already searched stackoverflow but did not find an answer. I also tried str.equals(""), as well as returning a boolean with php but nothing seemed to work.

Javascript:

xhttp.onload = function(){
    alert(xhttp.responseText); //Here comes "true" or "false" just like I want it
    if(xhttp.responseText == "true"){ //This always gives me "ERROR and then the responseText (which is true or false)
        alert("TRUE");
    }else if(xhttp.responseText == "false"){
        alert("FALSE");
    }else{
        alert("ERROR" + xhttp.responseText);
    }
};

PHP:

if(count($echo)==3){
            if($tag==$echo[2]){
                echo "true";
                break;
            }else if($i == (count($fahrten)-1)){
                echo "false";
            }
        } 

Expected result: alert with "TRUE" or "FALSE" actual result: alert with "Error" followed by the responseText

I hope some of you can help me and the question is not too stupid I'm stil learning an it is for a scholl project.

Answer 1

Try trimming responseText before comparing:

xhttp.onload = function(){
    var responseText = xhttp.responseText.trim();

    alert(responseText); //Here comes "true" or "false" just like I want it
    if(responseText  == "true"){ //This always gives me "ERROR and then the responseText (which is true or false)
        alert("TRUE");
    }else if(responseText  == "false"){
        alert("FALSE");
    }else{
        alert("ERROR" + responseText );
    }
};