How to access to a java variable in javascript function

Question

I have a java file called myJavaFile.java. Inside this java file, I have the following java code:

private void addUploadscript() {

      //my java variable
    String fn = session.getUser();

    html.addElement("<script language=\"JavaScript\" type=\"text/javascript\">");
    html.addElement("function ajax_post(){");
    html.addElement("var hr = new XMLHttpRequest();");
    html.addElement("var url = \"http://localhost:8080/bunk/inf?cmd=Dialer.opts#\";");
    html.addElement("var vars = \"firstname=\"+fn;");
    html.addElement("\talert(vars)"); 
    html.addElement("hr.open(\"POST\",url,true);");
    html.addElement("hr.setRequestHeader(\"Content-type\",\"application/x-www-form-urlencoded\");");
    html.addElement("hr.onreadystatechange = function() {if (hr.readyState == 4 && hr.status == 200) {var return_data = \"my server is reached\";document.getElementById(status).innerHTML = return_data;} } ");
    html.addElement("hr.send(vars);");
    html.addElement("document.getElementById(status).innerHTML = \"processing....\";");
    html.addElement("}");
    html.addElement("</SCRIPT>");

}

I already tried to find my response by reading the other topics but I still can not resolve my problem. I actually tried to do it step by step and display my variables to make sure that I wrote everything fine.

Thank you very much for your help!

which variable ? fn ? If yes then just do this: html.addElement("var vars = \"firstname=\"+fn +"\;"); — mprabhat
– mprabhat, Commented Apr 20, 2016 at 19:32

Elliott Frisch · Accepted Answer · 2016-04-20 19:32:23Z

2

I believe you want to output fn directly, something like

html.addElement("var vars = \"firstname=" + fn + "\";");

Javascript allows you to use ' or " for String(s), and you could also use String.format(String, Object...). Like,

html.addElement(String.format("var vars = 'firstname=%s';", fn));

answered Apr 20, 2016 at 19:32

Elliott Frisch

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3 Comments

tatiana77 Over a year ago

Thank you very much for you reply, I corrected it. I actually am trying my "fn" java variable which is now "firstname" to a php application. This is my final code but I think I have another problem now, I do not know if "firstname' is sent or not. All I did is just put an alert in both cases (OK or non OK) but nothing is displayed. I also tried to set my "status" input type text on my java side but nothing is displayed. Please let me know if have an idea, I really appreciate that. Thank you.

Elliott Frisch Over a year ago

Huh? Why are you involving Java then? You can make a ReST call to your PHP from Java or from Javascript. Anyway, your question appears to be about embedding JavaScript in Java.

tatiana77 Over a year ago

Yes I am embedding javascript in Java. This is an existing application so I have to deal with it because everything is written in this way.

SanF · Accepted Answer · 2016-04-20 19:33:25Z

1

You should change this part of your code:

html.addElement("var vars = \"firstname=\"+fn;");

For this:

html.addElement("var vars = \"firstname=\"" + fn + "\";");

answered Apr 20, 2016 at 19:33

SanF

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21 Comments

tatiana77 Over a year ago

Thank you very much for you reply, I corrected it. I actually am trying my "fn" java variable which is now "firstname" to a php application. This is my final code but I think I have another problem now, I do not know if "firstname' is sent or not. All I did is just put an alert in both cases (OK or non OK) but nothing is displayed. I also tried to set my "status" input type text on my java side but nothing is displayed. Please let me know if have an idea, I really appreciate that. Thank you.

SanF Over a year ago

Can you post the generated HTML? If you are opening that page with Google Chrome, do you see any error in the developer console?

tatiana77 Over a year ago

Hello Sanf, I tried to put the generated html but it says that it's too long. I have the generated html. Is there any over way to send it here?

SanF Over a year ago

Post only the generated script tag, just to check if there is any js error.

tatiana77 Over a year ago

ajax_post({document.getElementById('buttonChat').style.display='none';var hr=new XMLHttpRequest();var url='localhost:9090/mibew/index.php/operator/login';var fn = document.getElementById('user_name').value; var vars = 'firstname='+fn;hr.open('POST',url,true);hr.setRequestHeader('Content-type','application/x-www-form-urlencoded');hr.onreadystatechange = function(){var return_data='';if (hr.readyState == 4 && hr.status ==200{return_data='ok';document.getElementById(status).innerHTML=return_data;}else{return_data='ko';document.getElementById(status).innerHTML =return_data;}}hr.send(vars);}

|

Zakaria Acharki · Accepted Answer · 2016-04-20 19:45:21Z

1

Just use single qoute ' instead of \" in all your code that will make it more cleanest, and replace this part :

html.addElement("var vars = \"firstname=\"+fn;")

By :

html.addElement("var vars = 'firstname='+fn;")

Hope this helps.

answered Apr 20, 2016 at 19:45

Zakaria Acharki

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1 Comment

tatiana77 Over a year ago

Thank you very much for you reply, I corrected it. I actually am trying my "fn" java variable which is now "firstname" to a php application. This is my final code but I think I have another problem now, I do not know if "firstname' is sent or not. All I did is just put an alert in both cases (OK or non OK) but nothing is displayed. I also tried to set my "status" input type text on my java side but nothing is displayed. Please let me know if have an idea, I really appreciate that. Thank you.

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