not able to check/uncheck a checkbox with Active Widgets Grid in Chrome

the requirement as follows,
i have four rows and three columns in Active Widgets Grid. in first column all are checkboxes. If i check one checkbox remaining are need to be disable and if i uncheck that checked one remaining are need to be enable.
the code which written is
for(var i=0;i<document.getElementsByName("selection").length;i++){
if(document.getElementsByName("selection")[i].checked ){
document.getElementsByName("selection")[i].disabled=false;
}else{
document.getElementsByName("selection")[i].disabled=true;
}
}


the problem with Chrome browser only it works fine in IE
can anyone provide the solution.