javascript - Round integer number to 1 decimal -

i using jquery knob , input value change through sliders.

window.onload = function(){    var elements=document.queryselectorall('input[type=range]')    for(var = 0; < elements.length; i++){        elements[i].addeventlistener('change',calcul , false);    } }  function calcul(){     var elements = document.queryselectorall('input[type="range"]')     var len = 0     var buf = 0     for(var i=0;i<elements.length;i++) {         if(elements[i].parentnode.parentnode.style.display != 'none'){             buf += parseint(elements[i].value)             len++         }     }     buf = len === 0 ? 0 : buf/len     document.getelementbyid("knob").value=buf;     $("#knob").trigger("change"); } 

now want round "buf" variable 1 decimal, tried use tofixed , math.round.... cant work, can please me?

edit:i used this, if use console.log goes well.

buf = len === 0 ? 0 : buf/len; gem_cijfer = buf.tofixed(1); document.getelementbyid("knob").value=gem_cijfer; document.getelementbyid("form_knob").value=gem_cijfer; $("#knob").trigger("change"); 

example problem, in console.log show 1.7. in input field of jquery knob shows 1.7000000000000002. see image below.

how solve problem

i dont understand why .tofixed , math.round not working can think of alternativeif willing process string.

checkthis

function roundtoone(val) { var length =val.indexof('.'); var newval= val.substring(0,length+2); return newval; } 

http://jsfiddle.net/8xqen/1/

dont forget add validations

edit

i dont think issue .tofixed , math.round knob

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