在网上看了很多用js 将光标移动到textarea的最后，但是看了很多垃圾方法，屁不管用，浪费时间，最近用到一个新方法

=IE支持document.selection
=Firefox，Chrome,Safari以及Opera都有selectionStart和selectionEnd属性

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function insertText(obj,str) {
    if (document.selection) {
        var sel = document.selection.createRange();
        sel.text = str;
    } else if (typeof obj.selectionStart === 'number' && 
            typeof obj.selectionEnd === 'number') {
        var startPos = obj.selectionStart,
            endPos = obj.selectionEnd,
            cursorPos = startPos,
            tmpStr = obj.value;
        obj.value = tmpStr.substring(0, startPos) + str + 
                    tmpStr.substring(endPos, tmpStr.length);
        cursorPos += str.length;
        obj.selectionStart = obj.selectionEnd = cursorPos;
    } else {
        obj.value += str;
    }
}
function moveEnd(obj){
    obj.focus();
    var len = obj.value.length;
    if (document.selection) {
        var sel = obj.createTextRange();
        sel.moveStart('character',len);
        sel.collapse();
        sel.select();
    } else if (typeof obj.selectionStart == 'number' && typeof obj.selectionEnd == 'number') {
        obj.selectionStart = obj.selectionEnd = len;
    }

} 

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