Passing parameters to express node.js via java script

Question

I am using javascript,html,nodejs,express and mysql to retrieve values from database and pass it back to html .

Here , the user enters a domain in the 'btnSearch' text box and presses Load button . The javascriot calls the /getallusers code in app.js . This function should access the database and return the result .

The problem i am facing is : i am not able to pass on the value in 'btnSearch' to the app.js . If i include the tags in html , then the request does not go to /getallusers .instead it goes to /hi.html?input=Music . So i have not used the tag .

The html page is as below :
var xmlDoc = null ;

function load() {
var str = document.getElementById('btnSearch');
alert(str);
if (typeof window.ActiveXObject != 'undefined' ) {
  xmlDoc = new ActiveXObject("Microsoft.XMLHTTP");
  xmlDoc.onreadystatechange = process ;
}
else {
  xmlDoc = new XMLHttpRequest();
  xmlDoc.onload = process ;
}
xmlDoc.open( "GET", "/getallusers?input="+str, true );
xmlDoc.send( null );
}

function process() {
if ( xmlDoc.readyState != 4 ) return ;
document.getElementById("output").value = xmlDoc.responseText ;
}
}</script><body>
<input type="text" name="input" id="btnSearch" />
<textarea id="output" cols='70' rows='40'><empty></textarea>
<br></br>
<button onclick="load()">Load</button> 
<button onclick="empty()">Clear</button>
</body>
</html>

My express function is :

    app.get('/getallusers', function (req, res) {
    var input_domain=req.query.input;
    console.log(input_domain);
    connection.query('SELECT DBName FROM CrawlerDBInfo where Domain ='+"'"+input_domain+"'"+';', function (error, rows, fields) {
        res.writeHead(200, {
            'Content-Type': 'text/plain'
        });
        str = '';
        for (i = 0; i < rows.length; i++)
        str = str + rows[i].DBName + '\n';
        res.end(str);
    });
});

Damodaran · Accepted Answer · 2013-11-22 06:30:03Z

3

you can accept data using routes in node.js app as

app.get('/getallusers/:input', function (req, res) {
    var input_domain=req.params.input;
    console.log(input_domain);
    connection.query('SELECT DBName FROM CrawlerDBInfo where Domain ='+"'"+input_domain+"'"+';', function (error, rows, fields) {
        res.writeHead(200, {
            'Content-Type': 'text/plain'
        });
        str = '';
        for (i = 0; i < rows.length; i++)
        str = str + rows[i].DBName + '\n';
        res.end(str);
    });
});

by using ":" in your routes you can specify parameter. And from your javascript in UI you send get call with the parameter as

localhost:3003/getallusers/inputdomainvalue

SO the above route will be executed. For more information see api

answered Nov 22, 2013 at 6:30

Damodaran

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2 Comments

Rasika Vijay Over a year ago

i tried this and i am getting the error : Cannot GET /127.0.0.1:1213/getallusers/Music . i have a doubt. do we need to specify the get call as the following ? localhost:3003/getallusers/?input=domainvalue

Damodaran Over a year ago

You need to add a route in your application as app.get('/getallusers/:input', function (req, res) {var input_domain=req.params.input;//here you will get value music});

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