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<title>Document</title>
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var input=document.querySelector("input");
input.addEventListener("select",selectHandler);
function selectHandler(e){
// console.log(input.value,input.selectionStart,input.selectionEnd)
// input.value=input.value.slice(0,input.selectionStart)+input.value.slice(input.selectionStart,input.selectionEnd).toUpperCase()+input.value.slice(input.selectionEnd);
input.value=input.value.split("").reduce(function(v,t,i){
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else v+=t;
return v;
},"");
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