Mouse position in D3

I just wanted to get the mouse position using D3 by using the following code:

var x = 0;

svg.on('mousemove', function () {
   x = d3.mouse(this)[0];         
});

but x is always equal to 0. By using console.log(), I can see that x value is getting changed just inside the function() but out of it x got its initial value of 0.

How can I save the x value and use it later in my application?

Answers:

Answer

You have to use an array. That will store x and y like:

var coordinates= d3.mouse(this);
var x = coordinates[0];
var y = coordinates[1];

// D3 v4
var x = d3.event.pageX - document.getElementById(<id-of-your-svg>).getBoundingClientRect().x + 10
var y = d3.event.pageY - document.getElementById(<id-of-your-svg>).getBoundingClientRect().y + 10
Answer

You can understand the click and drag function through this example very well.Hope it will helps..

 var point = d3.mouse(this)
  , p = {x: point[0], y: point[1] };

http://jsfiddle.net/mdml/da37B/

Answer

V3:

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', function() {
      console.log( d3.mouse(this) ) // log the mouse x,y position
    });

V4 and V5:

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', function() {
      console.log( d3.event.pageX, d3.event.pageY ) // log the mouse x,y position
    });
Answer

I suspect you might be trying some like:

var x = 0;

svg.on('mousemove', function () {
   x = d3.mouse(this)[0];         
});

console.log(x);

Unless you have super fast hands, this will always write "0" to the console because the whole script executes while you are reaching for the mouse. Try putting your snippet directly into the console, move the mouse around and then type "x" into the console. You should see the latest x value.

I hope this helps, but I may have misunderstood the question.

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