js 批量空格替换成 

<textarea contenteditable="true" id="t" onkeyup="this.value=this.value.replace(/\s+/g,'')" rows="3" placeholder="请填写详细地址,不超过100个字"></textarea>

<script>
    var d = document.getElementById( "t" );
    document.addEventListener( "keyup", function() {
        d.innerHTML = d.innerHTML.replace(/\s+/g,'');
    } );

var a = "hello  word word  word  word"; 
var b = a.replace(new RegExp(" ", "gm"), "&nbsp;"); 
console.log(b); 

//终极杀招
String.prototype.replaceAll = function(reallyDo, replaceWith, ignoreCase) { 
    if (!RegExp.prototype.isPrototypeOf(reallyDo)) { 
        return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi": "g")), replaceWith); 
    } else { 
        return this.replace(reallyDo, replaceWith); 
    } 
} 
</script>