javascript 文章截取部分无损html显示实现代码

var br = {};
br.spTags = ["img","br","hr"];/*不需要成对出现的标记*/
br.contain = function(arr,it){
for(var i=0,len=arr.length;i<len;i++){
if(arr[i]==it){
return true;
}
}
return false;
}
br.subArtc = function(article,worldNum){
var result = [];
/*首先截取需要的字串*/
var wcount = 0;
var startTags = [],endTags = [];
var isInTag = false;
for(var i=0,len=article.length;i<len;i++){
var w = article[i];
result.push(w);
if(w=="<"){
isInTag = true;
}
if(!isInTag){
wcount++;
if(wcount==worldNum){
break;
}
}
if(w==">"){
isInTag = false;
}
}
/*对字串进行处理*/
var j=0;
isInTag = false;
var isStartTag = true;
var tagTemp = "";
while(j<i){
w = result[j];
if(isInTag){
if(w==">" || w==" " || w=="/"){
isInTag = false;
if(isStartTag){
startTags.push(tagTemp);
}else{
endTags.push(tagTemp);
}
tagTemp = "";
}
if(isInTag){
tagTemp+=w;
}
}
if(w=="<"){
isInTag = true;
if(result[j+1]=="/"){
isStartTag = false;
j++;
}else{
isStartTag = true;
}
}
j++;
}
/*剔除img,br等不需要成对出现的标记*/
var newStartTags = [];
for(var x=0,len=startTags.length;x<len;x++){
if(!br.contain(br.spTags,startTags[x])){
newStartTags.push(startTags[x]);
}
}
/*添加没有的结束标记*/
var unEndTagsCount = newStartTags.length - endTags.length;
while(unEndTagsCount>0){
result.push("<");
result.push("/")
result.push(newStartTags[unEndTagsCount-1]);
result.push(">");
unEndTagsCount--;
}
return result.join("");
};