function over_how() 
{
     document.images[2].src='js/buttons/how_b.png';
}

function out_how() 
{
     document.images[2].src='js/buttons/how.png';
}

function over_pricing() 
{
     document.images[3].src='js/buttons/pricing_b.png';
}

function out_pricing() 
{
     document.images[3].src='js/buttons/pricing.png';
}

function over_workflow()
{
     document.images[4].src='js/buttons/workflow_b.png';
}

function out_workflow()
{
     document.images[4].src='js/buttons/workflow.png';
}

function over_datasheet()
{
     document.images[5].src='js/buttons/datasheet_b.png';
}

function out_datasheet()
{
     document.images[5].src='js/buttons/datasheet.png';
}

function over_solution()
{
     document.images[6].src='js/buttons/solution_b.png';
}

function out_solution()
{
     document.images[6].src='js/buttons/solution.png';
}

function over_mxs_soft()
{
     document.images[7].src='js/buttons/mxs_soft_b.png';
}

function out_mxs_soft()
{
     document.images[7].src='js/buttons/mxs_soft.png';
}