Handling of selection through javascript

Question

Please refer to the link of my chart .

http://www.humblesoftware.com/finance/index (Customized this )

Basically the requirement is that , only one month of selection can be made at a point of time .(From the child chart)

If the selection is made from left side , i am simply adding 30 to the other value

xmin = Math.floor(area.x1);
xmax = xmin+30; 

But if the selection is made from the right side then how to handle this ??

(Means if the xmax is selected first then how can i handle the xmin value )??

• Chad: do the opposite...set xmax to the selected value and xmin to that value minus 30 days
• Kiran: Thank you chad , you mean xmax = Math.ceil(area.x2); and xmin = xmax-30 ?? But how can i handle this ?? any sample code please
• Brad Christie: @Chad: So depending where area.x1 is clicked, this could potentially back or forward-date? Seems like a confusion solution to the end-user.

Answer 1

Without knowing too much about the situation, something like this should do:

// set the xmin to where they click
xmin = Math.floor(area.x1);
// make x-max the + 30 as you normally do
xmax = xmin + 30;
// now add a check to make sure we're not off the chart
// if we are, make the chart's last possible X value the
// x max, and subtract 30 from that to go backwards (and
// it may be a good idea to check if xmin is under the
// chart's min x value.
if (xmax > chart.xmax){
 xmax = chart.xmax;
 xmin = xmax - 30;
 if (xmin < chart.xmin){
 xmin = chart.xmin;
 }
}

• Kiran: Brad , this way i obtain the xmin and the xmax values xmin=Math.floor(area.x1); xmax = Math.ceil(area.x2); could you please tell how ur code works ??
• Brad Christie: @Kiran: So check against each other to find the greater number (for the top range) and lesser number (for the bottom range)? xmin = area.x1; xmax = area.x2; if (xmin > xmax){ xmin = xmin + xmax; xmax = xmin - xmax; xmin = xmin - xmax; } xmin = Math.floor(xmin); xmax = Math.ceil(xmax); possibly?