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<input type=button onclick='changeText(["...ТЕКСТ1...", "...ТЕКСТ2...", "...ТЕКСТ3..."])' value=obsc>
<script type="text/javascript">
function changeText(text){
document.getElementById('infa1').value = text[0];
document.getElementById('infa2').value = text[1];
document.getElementById('infa3').value = text[2];
}
</script>
<textarea id="infa1" name="infa1"></textarea>
<textarea id="infa2" name="infa2"></textarea>
<textarea id="infa3" name="infa3"></textarea>